Here's some things we are told about the day of the Lord, which you apparently insist has been in progress for almost 2000 years unless I'm misunderstanding you.
Amos 5:18 Woe unto you that desire the day of the LORD! to what end is it for you? the day of the LORD is darkness, and not light.
19 As if a man did flee from a lion, and a bear met him; or went into the house, and leaned his hand on the wall, and a serpent bit him.
20 Shall not the day of the LORD be darkness, and not light? even very dark, and no brightness in it?
1 Thessalonians 5:2 For yourselves know perfectly that the day of the Lord so cometh as a thief in the night.
3 For when they shall say, Peace and safety; then sudden destruction cometh upon them, as travail upon a woman with child; and they shall not escape.
2 Peter 3:10 But the day of the Lord will come as a thief in the night; in the which the heavens shall pass away with a great noise, and the elements shall melt with fervent heat, the earth also and the works that are therein shall be burned up.
11 Seeing then that all these things shall be dissolved, what manner of persons ought ye to be in all holy conversation and godliness,
12 Looking for and hasting unto the coming of the day of God, wherein the heavens being on fire shall be dissolved, and the elements shall melt with fervent heat?
Even though you appear to admit the thousand years and the day of the Lord speak of the same period of time, and unless you are a Preterist, which I don't take you to be, how then do you find it reasonable 1 Thessalonians 5:2 and 2 Peter 3:10 already came as a thief in the night 2000 years ago? If you argue that those particular verses are still future, how can you then be arguing that the DOTL has been in progress for nearly 2000 years?
The Day of the Lord coming was fulfilled when Messiah came. Have you ever done a search in the OT of 'Day of the Lord'? Each of the 24 verses from the Old Testament (KJV) the prophets write of the Day of the Lord as a day of wrath, and destruction against the enemies of the Lord. That's because all the prophets who prophesy about the coming of the Messiah, as the Day of the Lord, foresee Messiah to come not only to redeem the saints, but they seem especially focused on Him coming with destruction and wrath.
The prophets were not expecting or prophesying about two separate comings, but one. And all the prophets prophesied about the Messiah who would come in the Day of the Lord has been and is being fulfilled in this time called the Day of the Lord and likened to a thousand symbolic years. But what the prophets did not foretell or understand is that after His sacrificial death He would come a second time in wrath to make a full end of all His enemies.
Consider for instance the words of the prophet Joel. Peter in the book of Acts tells us the day of Pentecost and the outpouring of the Holy Spirit on all flesh is fulfillment of Joel's prophesy. But listen to the prophesy, it sounds as though this is fulfillment of the Day of the Lord the OT prophets foretell will be fulfilled when Messiah came, not some two thousand plus years later.
This is a picture of Messiah to come in the Day of the Lord when all these things Joel foretells will come to pass. What Joel's prophesy does not tell us is that his prophetic words began to be fulfilled at Pentecost but would not be completely fulfilled until the second coming of the Messiah when Christ will destroy all His enemies when He comes the second time.
Joel envisioned all of this as the Day of the Lord when Messiah came to earth to fulfill all that is written concerning Him. Joel did not see two comings of the Messiah, or two day of the Lord events, but ONE. And that Day of the Lord has come when Messiah came to earth the God-Man as the suffering servant but will come again to fulfill the words of prophesy by destroying every enemy, and usher in the next age of eternity.
First the beginning of the Day of the Lord coming when Jesus Christ was born, and then the earth goes through this time (a thousand symbolic years) for building the Kingdom of heaven as the Gospel is proclaimed unto all the earth, and whoever believes by grace through faith enters into the Kingdom. Then at the end of this symbolic time, Christ comes again, not to save His people, it's too late for that, but to destroy every enemy the prophets foretell He will at His coming with judgment and wrath.
Acts 2:14-21 (KJV) But Peter, standing up with the eleven, lifted up his voice, and said unto them, Ye men of Judaea, and all
ye that dwell at Jerusalem, be this known unto you, and hearken to my words: For these are not drunken, as ye suppose, seeing it is
but the third hour of the day. But t
his is that which was spoken by the prophet Joel; And it shall come to pass in the last days, saith God, I will pour out of my Spirit upon all flesh: and your sons and your daughters shall prophesy, and your young men shall see visions, and your old men shall dream dreams: And on my servants and on my handmaidens I will pour out in those days of my Spirit; and they shall prophesy: And I will shew wonders in heaven above, and signs in the earth beneath; blood, and fire, and vapour of smoke: The sun shall be turned into darkness, and the moon into blood, before that great and notable day of the Lord come: And it shall come to pass, that whosoever shall call on the name of the Lord shall be saved.
If you willing to admit that the thousand years and the day of the Lord speak of the same era of time, but then are willing to accept it is not reasonable after all to have the day of the Lord beginning 2000 years ago, shouldn't that mean you have no choice but to believe the thousand years are future still since you see the day of the Lord meaning the entire thousand years? Or if not, shouldn't that mean that you have no choice but to abandon the idea altogether, that the day of the Lord is meaning the entire thousand years?
What you are forgetting is that the New Testament is written after the advent of the prophesied Messiah who would come in the Day of the Lord, symbolized a thousand years. Therefore, Paul is writing about the second coming, that is also called the Day of the Lord. But when Christ comes the second time the prophesy of old will finally be fulfilled because the Messiah has come and the Day of the Lord they prophesied would come will be finished, and the Day (one) of the Lord the New Testament foresees will also be finished.
BTW, you seem to be the only Amill I'm aware of that would conclude that the day of the Lord equals the entire thousand years. Most Amills conclude that the day of the Lord does not even involve the thousand years, that it is after the thousand years sometime during satan's little season being when the DOTL initially begins.
David, those of us who profess to believe Amill is truth are individuals. We don't all explain our understanding of Amil doctrine in the same way. To be honest I appreciate like-minded people who have similar views as my own. But I try to use the Bible alone to guide my understanding of biblical doctrine. I haven't heard another person professing Amill teach the thousand years are sometime during Satan's little season. The very definition of Amill requires a belief that the thousand years symbolizes time between the first and second coming of Christ. Some may have a difficult time understanding about how time can still exist during Satan's little season. But that's most likely because they might still be trying to understand how time shall be no more when the seventh trumpet begins to sound, and Satan's little season of time can both be true.
Hope this explains my position in a way you can comprehend.
With this understanding it's easy to understand why I have a problem with the understanding the OP preposes regarding the thousand years and the Day of the Lord as a way to gage the age of the earth. Because the thousand years are indeed the Day of the Lord, symbolizing not all time from creation, but all time given the New Covenant Church to build the Kingdom of heaven through the Gospel and power of the Holy Spirit.