In Matthew 24 and Mark 13 and Luke 21, Jesus is describing events that will take place during the great tribulation.
Some of the things that take place during the great tribulation are going to be really scary and some people might think that no one with faith will survive.
But Jesus says, "Truly I say to you that this generation will by no means pass away until all these things happen," meaning that faithful Christians who are alive when the great tribulation starts would survive the great tribulation even though it's scary and make it to the time at the end of the tribulation when Jesus would come on the clouds and everybody would see him.
When Jesus went up into the clouds, people saw him. People will see him again when he gets here in Kingdom power to fix everything.
The word "generation" has nothing to do with calculating the times and seasons regarding the day and the hour the Kingdom would begin. It also has nothing to do with 1914. Jesus said not to even try to calculate when he would begin ruling in Kingdom power. The phrase that sometimes gets translated "the times of the Gentiles" would be better translated "appointed times of the nations" because another expression for the great tribulation is the appointed times of the nations. Daniel and Revelation show that that great tribulation will be 3 1/2 years long. It will be the time the UN destroys all religious institutions and oppresses people of faith to an extreme degree. The great tribulation is "the appointed times of the nations" to trample true Christians.
Jesus didn't come into Kingdom power in 1914. If that date could have been calculated from the scriptures, then he himself would have known it back when he walked the earth. Instead he said, no man knows the day or the hour the Kingdom would begin, not even him, only the Father.
Just like Jannes and Jambres seemed to do "miracles" that "came true" but they were really fakers and Satan just did tricks, so in a similar way when Russell and the Miller-type people said "1914!" because of numerology-pyramidology-whatever, Satan got in there and did his tricks again to make it seem like that "prophecy" of Russell came true. The book of Job shows the Devil can cause problems like plague-type stuff. The wicked one is called "the ruler of the world" and if he wants to set up a world war like WWI or WWII, certainly he is able. We can all see that Russell and many others from the borg fit the descriptions in 2 Timothy 3:1-5 about those who have a form of godly devotion and prove false to its power. The verses go on to say: "Now in the way that Janʹnes and Jamʹbres opposed Moses, so these also go on opposing the truth. Such men are completely corrupted in mind, disapproved as regards the faith. Nevertheless, they will make no further progress, for their folly will be very plain to all, as it was with those two men."
Second Thessalonians 2:9-12 says "But the lawless one’s presence is by the operation of Satan with every powerful work and lying signs and wonders and every unrighteous deception for those who are perishing, as a retribution because they did not accept the love of the truth in order that they might be saved. That is why God lets a deceptive influence mislead them so that they may come to believe the lie, in order that they all may be judged because they did not believe the truth but took pleasure in unrighteousness."
It's not surprising the "lawless ones" would have "powerful work and lying signs." How many people were misled by the 1914 thing? A lot.
But now "their folly" is "very plain to all". It's going to be a lot "plainer to all" when Jehovah's Witnesses as an institution are attacked by the nations at the beginning of the great tribulation. Jehovah will make it plain to everybody that those GB/FDS guys are disapproved.
Jesus didn't take the throne in 1914, but the prophecy in Daniel 11 and 12 shows he will take the throne very soon. When Jesus takes the throne in heaven, the first thing he will do is cast the Devil out of heaven. The Devil will get the UN all riled up to destroy religious people. God will allow all the religious institutions to be destroyed. Individuals will survive, and Jesus will make sure the Christian congregation he founded is refined and restored. People out of all denominations who have the right heart will be gathered together, and then a great crowd of right-hearted people who don't know God will also be gathered, just like a great crowd of Egyptians and others were gathered when it was time to leave Egypt. It's going to be a long 3 1/2 years that the UN will rule. We will need a lot of love for each other. There is so much work to do during the days ahead. Thank God it's Jesus and the angels who will be taking the lead in the congregation instead of any imperfect humans!