The dates in the NWT are based more on late tradition and wishful thinking than actual evidence. Most scholars do not agree with the Society on the dates of the gospels, Ephesians, the Pastorals (1, 2 Timothy, Titus), and the catholic epistles (Hebrews, James, 1, 2 Peter, Jude).
A few of the post-apostolic books in the NT do indeed comment on the death of the apostles. In particular, Christians suffered from the effects of cognitive dissonance because of unfulfilled apostolic prophecy, as well as experienced an increased hierarchical organization in the Church (cf. the Pastorals). The epistle of Jude, written sometime between AD 70-100, exhorted Christians to recall what the former apostles had taught "beforehand":
"But you, beloved, ought to remember the words that were spoken beforehand (proeirémenón) by the apostles of our Lord Jesus Christ, that they were saying to you, 'In the last time (eskhatou tou khronou) there shall be mockers, following after their own ungodly lusts.' These are the ones who cause divisions, wordly-minded, devoid of the Spirit" (Jude 17-19).
The apostles were no longer around to give guidance to the Christian community in this time of crisis. Sometime later in the second century AD (see the following thread on its dating and authorship), the pseudonymous author of 2 Peter plagiarized the text of Jude but was even more explicit on the situation:
"I am stirring up your sincere mind by way of reminder, that you should remember the words spoken beforehand (proeirémenón) by the holy prophets and the commandment of the Lord and Savior spoken by your apostles. Know this first of all, that in the last days (eskhatón tón hémerón) mockers will come with their mocking, following after their own lusts and saying, 'Where is the promise of his coming? For ever since the fathers (hoi pateres) fell asleep [in death] (ekoiméthésan), all continues just as it was from the beginning of creation." For when they maintain this, it escapes their notice that ... with the Lord one day is as a thousand years, and a thousand years as one day. The Lord is not slow about his promise, but is patient toward you, not wishing for any to perish but for all to come to repentence....You, therefore, beloved, knowing this beforehand (proginóskontes), be on your guard lest you fall from your own steadfastness" (2 Peter 2:1-5, 8-9, 17).
Here the author makes direct reference to the death of the first generation (the "fathers") and the failure of Christ's parousia to appear as expected. The author rationalizes the failed prophecy by saying that it could take as long as a thousand years to happen and in the meantime the Lord is patiently waiting for as many people to be saved as possible. Again, the "apostles" were already in the past, so that their commands could be lumped together with the words of the OT prophets as equally "spoken beforehand".
It was during this period that Revelation was published to keep apocalyptic expectations in the forefront. There is copious evidence that many of the Gentile churches, especially in Asia Minor, were setting aside such expectations for more mundane worldly concerns. Thus, the church at Ephesus was said to "have left your first love," and to the church of Sardis, the apocalypsist made Jesus say: "I know your deeds, that you have a name that you are alive, but you are dead. Wake up, and strengthen the things that remain....remember what you have received and heard, and keep it and repent. If you do not wake up, I will come like a thief" (Revelation 2:4-5, 3:1-3). To the church of Laodicea, John complained that they were "lukewarm" because they "have become wealthy and have need of nothing" (3:15-17). Similarly, there was the situation about Valens, presbyter of the Philippian church, who fell away due to love of money (Polycarp, Phil. 11:1-2), and the similar situation of the children of Hermas of Rome (cf. Shepherd, Vision 1.3.1-4; 2.6.1-8), as well as the general "lack of community spirit" in the church where people "exult in their wealth" and the leaders "are calloused and don't want to cleanse their hearts" (Vision 3.9.4-10). There were also strenuous efforts to impose a new hierarchical organization to the churches (cf. the bishops, presbyters, and deacons of the Pastorals and the epistles of Ignatius and Polycarp), which was resented by some and led to the defection of certain churches (who did not want such leadership) from the growing "universal" (katholike) church. And there was an ongoing theological struggle of the proto-orthodoxy in trying to define its beliefs and reject certain older beliefs as heretical. Thus we read in early second century writings (100-150 AD):
"You tolerate the woman Jezebel, who calls herself a prophetess, and she teaches and leads my bondservants astray, so that they commit immorality and eat things sacrificed to idols and I gave her time to repent and she does not want to repent of her immorality....But I say to you, the rest who are in Thyatira, who do not hold this teaching, who have not known the deep things of Satan, as they call them -- I place no burden on you" (Revelation 2:20-24).
"For many deceivers have gone out into the world, those who do not acknowledge Jesus Christ as coming in the flesh. This is the deceiver and the antichrist. Watch yourselves, that you might not lose what we have accomplished. Anyone who goes too far and does not abide in the teaching of Christ does not have God...If anyone comes to you and does not bring this teaching, do not receive him into your house, and do not give him a greeting" (2 John 7-10)
"Therefore, as the Lord did nothing without the Father, either by himself or through the apostles, so you must not do anything without the bishop and the presbyters. Do not attempt to convince yourselves that anything done apart from the others is right....Do not be deceived by strange doctrines or antiquated myths, since they are worthless. For if we continue to live in accordance to Judaism, we admit that we have not received grace....If then those who had lived in antiquated practices came to newness of hope, [they would] no longer keep the Sabbath but living in accordance with the Lord's Day, on which our life also arose through him and his death (which some deny)" (Ignatius, Magnesians 7:1-9:1).
"[Jesus] suffered all these things for our sakes, in order that we might be saved; and he truly suffered just as he truly raised himself -- not, as certain unbelievers say, that he suffered in appearance only. It is they who exist in appearance only. Indeed, their fate will be determined by what they think: they will become disembodied and demonic....What good does it do me if someone praises me but blasphemes my Lord by not confessing that he was clothed in flesh? Anyone who does not acknowledge this thereby denies him completely and is clothed in a corpse. Given that they are unbelievers, it did not seem worthwhile to me to record their names....Note well those who hold heretical opinions about the grace of Jesus Christ which came to us; note how contrary they are to the mind of God. They have no concern for love, none for the widow, none for the orphan, none for the oppressed...They abstain from the Eucharist and prayer, because they refuse to acknowledge that the Eucharist is the flesh of our Savior Jesus Christ" (Ignatius, Smyrnaeans 2:1, 5:2-3, 6:2).
"The Spirit explicitly says that in later times some will fall away from the faith, paying attention to deceitful spirits and doctrines of demons, by means of the hypocrisy of liars seared in their own conscience as with a branding iron, men who forbid marriage and advocate abstaining from certain foods...Have nothing to do with worldly myths fit only for old women.....Avoid worldly and empty chatter, for it will lead to further ungodliness, and their talk will spread like gangrene. Among them are Hymenaeus and Philetus, men who have gone astray from the truth saying that the resurrection has already taken place and thus they upset the faith of some" (1 Timothy 4:1-3, 7; 2 Timothy 2:16-18).
"For everyone who does not confess that Jesus Christ has come in the flesh is antichrist, and whoever does not acknowledge the testimony of the cross is of the Devil, and whoever twists the sayings of the Lord to suit his own desires and claims that there is neither resurrection nor judgment, well that person is the firstborn of Satan. Therefore let us leave behind the worthless speculation of the crowd and their false teachings, and let us return to the word delivered to us from the beginning" (Polycarp, Philippians 7:1-2).
"There will be false teachers among you, who will secretly introduce destructive heresies, even denying the Master who bought them, bringing swift destruction upon themselves....After they have escaped the defilements of the world by the knowledge of the Lord and Savior Jesus Christ, they are again entangled in them and are overcome, becoming worse than in the beginning...In all [Paul's] letters, he speaks of these things, in which there are some things hard to understand, which the untaught and unstable twist, as they do also the rest of the Scriptures, to their own destruction" (2 Peter 2:1, 20; 3:16).
Hopefully that gives you some concept of how the proto-orthodoxy reacted to the death of the apostles and their competition with the spectrum of Christianity that did not move in lockstep with the beliefs and practices of the post-apostolic churches headed by bishops, deacons, and presbyters.
