You overlooked verse 38. Jesus said that their house would be left "desolate." But He left the door open for THAT generation to still accept Him, which they did not.
Note that the verb is conditional. Jesus said, "You may not see me again until you say, 'Blessed is He who comes in the name of the Lord.' " That generation passed away and never said it. Therefore, their house is left "desolate."
Jesus said NOTHING about the kingdom being taken away from the nation that now possesses it.
Where is the reference to THAT generation? Their house is left desolate, yes, but not forever:
Zechariah 12:10-11
“And I will pour out on the house of David and the inhabitants of Jerusalem a spirit of grace and supplication. They will look on me, the one they have pierced, and they will mourn for him as one mourns for an only child, and grieve bitterly for him as one grieves for a firstborn son. On that day the weeping in Jerusalem will be as great as the weeping of Hadad Rimmon in the plain of Megiddo.
Zechariah 14:2-5
I will gather all the nations to Jerusalem to fight against it; the city will be captured, the houses ransacked, and the women raped. Half of the city will go into exile, but the rest of the people will not be taken from the city. Then the Lord will go out and fight against those nations, as he fights on a day of battle. On that day his feet will stand on the Mount of Olives, east of Jerusalem, and the Mount of Olives will be split in two from east to west, forming a great valley, with half of the mountain moving north and half moving south. You will flee by my mountain valley, for it will extend to Azel. You will flee as you fled from the earthquakea in the days of Uzziah king of Judah. Then the Lord my God will come, and all the holy ones with him.
Jesus is not coming back
until those that he came to (the Jews) who rejected him, repent and believe him. We must conclude then, that they will repent, else Jesus isn't coming back (and we know that is not a possibilty).
Only one translation from biblehub.com has 'may' as a translation (see last one in the list).
New International Version (©2011)
For I tell you, you will not see me again until you say, 'Blessed is he who comes in the name of the Lord.'"
New Living Translation (©2007)
For I tell you this, you will never see me again until you say, 'Blessings on the one who comes in the name of the LORD!'"
English Standard Version (©2001)
For I tell you, you will not see me again, until you say, ‘Blessed is he who comes in the name of the Lord.’”
New American Standard Bible (©1995)
"For I say to you, from now on you will not see Me until you say, 'BLESSED IS HE WHO COMES IN THE NAME OF THE LORD!'"
King James Bible (Cambridge Ed.)
For I say unto you, Ye shall not see me henceforth, till ye shall say, Blessed is he that cometh in the name of the Lord.
Holman Christian Standard Bible (©2009)
For I tell you, you will never see Me again until you say, He who comes in the name of the Lord is the blessed One'!"
International Standard Version (©2012)
I tell you, you will not see me again until you say, 'How blessed is the one who comes in the name of the Lord!'"
NET Bible (©2006)
For I tell you, you will not see me from now until you say, 'Blessed is the one who comes in the name of the Lord!'"
Aramaic Bible in Plain English (©2010)
For I say to you that you will not see me from now on, until you will say, 'Blessed is he who has come in the name of THE LORD JEHOVAH.'”
GOD'S WORD® Translation (©1995)
I can guarantee that you will not see me again until you say, 'Blessed is the one who comes in the name of the Lord!'"
King James 2000 Bible (©2003)
For I say unto you, you shall not see me again, till you shall say, Blessed is he who comes in the name of the Lord.
American King James Version
For I say to you, You shall not see me from now on, till you shall say, Blessed is he that comes in the name of the Lord.
American Standard Version
For I say unto you, Ye shall not see me henceforth, till ye shall say, Blessed is he that cometh in the name of the Lord.
Douay-Rheims Bible
For I say to you, you shall not see me henceforth till you say: Blessed is he that cometh in the name of the Lord.
Darby Bible Translation
for I say unto you, Ye shall in no wise see me henceforth until ye say, Blessed be he that comes in the name of the Lord.
English Revised Version
For I say unto you, Ye shall not see me henceforth, till ye shall say, Blessed is he that cometh in the name of the Lord.
Webster's Bible Translation
For I say to you, Ye shall not see me henceforth, till ye shall say, Blessed is he that cometh in the name of the Lord.
Weymouth New Testament
For I tell you that you will never see me again until you say, 'Blessed be He who comes in the name of the Lord.'"
World English Bible
For I tell you, you will not see me from now on, until you say, 'Blessed is he who comes in the name of the Lord!'"
Young's Literal Translation
for I say to you, ye
may not see me henceforth, till ye may say, Blessed is he who is coming in the name of the Lord.'