The 1914 chronology is Biblical, considering that the Jehovah's Witnesses read through the entire Bible, picked up on the chronology and considered previous movements' interpretations of the prophecies, and set chronologies according to it.
Aside from Charles Russell's examination of other religions and prophecies outside of the Bible, 1914 and several other dates are simply milestones in the chronology of the Bible and forecasted prophecies that the Bible gives on the end times.
Prophecies referring to both the short-term events at hand and a longer-range prophetic meaning in the future are not uncommon in the Bible.
Keep in mind that the messianic prophecies on Jesus Christ were also applied to King Solomon.
For the second prophecy of this passage, with "Who is the YOU" that acknowledges the Most High?, "Who is the YOU that was “driving away from men” for 2520 years"?, "Who is the YOU that dwelt “with the beast of the field” and ate vegetation “just like bulls” from 607 BCE till 1914?", etc., this is taking the imagery of the prophecy's references far too literally.
You might as well deny that Jesus is the messiah, because many prophecies that refer to him don't have Jesus Christ fitting into the imagery literally, nor are many of the Bible's references to Jesus Christ as having fulfilled scripture taken in the perfect context.
Take some prophecies on Jesus Christ into consideration:
8But about the Son he says,
"Your throne, O God, will last for ever and ever,
and righteousness will be the scepter of your kingdom.
9You have loved righteousness and hated wickedness;
therefore God, your God, has set you above your companions
by anointing you with the oil of joy."
This verse from the New Testament is referring to prophecy on Jesus Christ, right?
The verse refers to Psalm 45:6-7. Consider what else the passage says:
6 Your throne, O God, will last for ever and ever;
a scepter of justice will be the scepter of your kingdom.
7 You love righteousness and hate wickedness;
therefore God, your God, has set you above your companions
by anointing you with the oil of joy.
8 All your robes are fragrant with myrrh and aloes and cassia;
from palaces adorned with ivory
the music of the strings makes you glad.
9 Daughters of kings are among your honored women;
at your right hand is the royal bride in gold of Ophir.
10 Listen, O daughter, consider and give ear:
Forget your people and your father's house.
Was Jesus Christ married when he was anointed?
Who was the queen of Jesus Christ?
When were there "daughters of kings... among your honored women" and at Jesus Christ's "right hand is the royal bride in gold of Ophir"?
Consider the rest of the messianic prophecy of Psalm 45.
When did Jesus fall in love? (Psalm 45:11)
When were Jesus and his "wife" given gifts by the King of Tyre? (Psalm 45:12)
When did Jesus have children? (Psalm 45:16)
Since when did any of that happen?
The passage of Psalm 45 refers to King Solomon, not Jesus Christ, but it is applied to Jesus Christ by the writer of Hebrews because it deals with the messianic covenant. Psalm 45 is an inspired writing of David after his son King Solomon inherited his throne.
This is an inspired writing on the covenant with King David. God put David in a covenant when he was king.
Consider another passage on that. Hebrews 1:5, with "I will be his Father, and he will be my Son," refers to part of that covenant as being fulfilled with Jesus Christ. The Old Testament scripture being referred to with this prophecy is 2 Samuel 7:12-16 (or 1 Chronicles 17:11-14; it's the same).
However, the covenant says that it will happen once David's "days are over" and that he will build God's home (temple). (2 Samuel 7:13)
Did Jesus build a temple for God when he came?
Was Jesus punished by God for his wrongdoing when he came? (2 Samuel 7:14)
No, but these parts of the covenant aren't supposed to be applied to Jesus Christ verbatim. Even 1 Chronicles 22:7-10 says that the "son" that God was speaking of in the covenant was Solomon. Does this mean that King Solomon is actually "the Son of God?"
Was the writer of Hebrews wrong? Was the writer of Hebrews "a false prophet?"
He simply applied the covenant to the messianic prophecy. The covenant and prophecy is not applied verbatim.
Many Jews before Jesus Christ's time were anticipating and looking out for fulfillment of the events and keeping an eye on the warnings and signs God gave in the Old Testament in respect to the covenant with King David and the messianic prophecy.
Today, many adherents of Judaism criticize the idea of Jesus being the messiah and take the scriptures more literally and critically than you do here in disregarding that Jesus could possibly be the messiah.
If you don't accept the chronology, alright. That's undoubtedly reasonable. When Jehovah's Witnesses determine chronologies, it's simply that: chronologies:
The Watchtower October 15, 1966 Rejoicing over "God's Sons of Liberty" Spiritual Feast
At the Baltimore assembly Brother Franz in his closing remarks made some interesting comments regarding the year 1975. He began casually by saying, "Just before I got on the platform a young man came to me and said, 'Say, what does this 1975 mean? Does it mean this, that or any other thing?'" In part, Brother Franz went on to say: 'You have noticed the chart . It shows that 6,000 years of human experience will end in 1975, about nine years from now. What does that mean? Does it mean that God's rest day began 4026 B.C.E.? It could have. The Life Everlasting book does not say it did not. The book merely presents the chronology. You can accept it or reject it. If that is the case, what does that mean to us?
-and, indeed, some Jehovah's Witnesses have become zealous over the chronologies in the past, sometimes anticipating beyond what's determined and discussed in the publications, taking it up to some of the meetings. It all falls in line with the fact that they believe in God and desire to acknowledge God's teachings, warnings, and commands. (Jehovah's Witnesses believe that the Bible is the word of God, reliable, and of high authority. Don't forget that the religion formed after Russell had doubts about religion and started examining world religions in an effort to find true religion, the right direction.)
Many Jehovah's Witnesses disregard some of the prophecies, even today, but what's with this about the chronology being un-Biblical? The Jehovah's Witnesses read the Bible and saw the chronology over the messiah's establishment on the throne. (As a result, Jehovah's Witnesses don't vote or get involved in politics. They are Christians who vote for the messiah, not man.)
Consider some simpler messianic prophecy (Isaiah 42:1-9) and what God says at the end:
9 See, the former things have taken place,
and new things I declare;
before they spring into being
I announce them to you."
Isaiah 42:1-9 is on Jesus Christ and was quoted in the Gospel accounts; e.g. Matthew 12:15-21 on Isaiah 42:1-4, and Luke 2:32 on Isaiah 42:6. Is it unreasonable to anticipate such prophecy?
What did Jesus Christ himself tell the Christians to do?
42"Therefore keep watch, because you do not know on what day your Lord will come. 43But understand this: If the owner of the house had known at what time of night the thief was coming, he would have kept watch and would not have let his house be broken into. 44So you also must be ready, because the Son of Man will come at an hour when you do not expect him.
Jesus Christ tells the Christians to anticipate his coming!
In Matthew 24, Jesus Christ is telling us the signs of the end times.
The same account is recorded in Luke 21, which you have cited from.
If you'd like to see the details of the chronology and how they are generally put together, for reference, you can see this post where I organized the details of what's known about the messianic prophecy (this was from the other thread and you probably already saw it):
I've explained it there as well as the justification, but, to summarize it, yes, Jesus Christ's coming discusses Jerusalem (the capital of Israel, "God's nation"), being trampled by Gentiles (Luke 21:20-24) and the Old Testament scriptures on exile, a number of which deal with prophecy, are applied to the chronology from Daniel surrounding the exile of Jerusalem's inhabitants.
1914 may be right; it may be wrong. It's one of several chronologies determined from the Bible.
It's simply odd, though, to think that Christians shouldn't be anticipating Jesus Christ's second coming, considering that Jesus repeatedly tells the Christians to do so (Matthew 24:27-28; Matthew 24:42-44; Luke 21:27; Luke 21:29-31) and the Apostle Paul mentioned it repeatedly as well (1 Corinthians 15:22-24; 1 Thessalonians 2:19; 1 Thessalonians 5:23). Do you think that Jesus doesn't want his followers to anticipate his second coming?