Hi, I am going to concentrate on the following passage you quoted:
"Who will be Jehovah's prophet to the nations, to speak to them everything that He should command? Who will be the modern Jeremiah? ... Back there, about forty years ago, that was the question. Today we may ask, how was the question answered? There are facts to show. We should not appeal to religious pride or boasting or self-made claims. We should appeal to the facts. Let facts speak for themselves. ... Whom has God actually used as his prophet? ... Jehovah's witnesses are deeply grateful today that the plain facts show that God has been pleased to use them." The Watchtower Jan. 15, 1959 pp. 40, 41.
The part you highlighted in bold shows the WTS presumptiousness, in declaring themselves "prophets" with NO permission whatsoever from Jehovah God.
Consider Jeremiah 23rd chapter, verses 16-17:
This is what Jehovah of armies has said: "Do not listen to the words of the prophets who are prophesying to YOU people. They are making YOU become vain. The vision of their own heart is what they speak-not from the mouth of Jehovah. They are saying again and again to those who are disrespectful of me, 'Jehovah has spoken: "Peace is what YOU people will come to have."' And [to] every one walking in the stubbornness of his heart they have said, 'No calamity will come upon YOU people.'
What are the prophets, the WTS doing? They are prophecying without permission! The message has indeed not come from Jehovah, so the prophecies failed to be fulfilled. This is precisely why Jehovah warned us through Jeremiah, in Jeremiah 23rd chapter.
However, there is something more. Verse 18 of the same chapter follows:
For who has stood in the intimate group of Jehovah that he might see and hear his word? Who has given attention to his word that he might hear it?
We know there will be an intimate group of people at the same time, who will indeed be taking heed of Jehovah's warnings, and giving attention to His word, the Bible, and will actually hear it. This group, you can be part of, there are people from this group RIGHT HERE on this forum. MDS, BJC2012 and Jr. If you stand in this group, associate with these people, then you will HEAR Jehovah's word, just as I believe I am hearing it.
However, verses 19-22 show the consequences of our choice, whether we stand in this intimate group or not:
Look! The windstorm of Jehovah, rage itself, will certainly go forth, even a whirling tempest. Upon the head of the wicked ones it will whirl itself. The anger of Jehovah will not turn back until he will have carried out and until he will have made the ideas of his heart come true. In the final part of the days YOU people will give YOUR consideration to it with understanding. "I did not send the prophets, yet they themselves ran. I did not speak to them, yet they themselves prophesied. But if they had stood in my intimate group, then they would have made my people hear my own words, and they would have caused them to turn back from their bad way and from the badness of their dealings."
Jehovah will carry out His judgement upon disobedient Israel. They are obeying the WTS "false prophets", obeying commands of men, committing IDOLATORY. If only the WTS did listen to Jehovah's words through the intimate group, they would have caused JW's earthwide to turn away from their badness.