Frankly, if any of us were prophets we don't know what we would say because God has yet to put His words in anyone's mouth. A prophet isn't told he is a prophet and then look around and see what he should talk about. True prophets speak what God is declaring.
Was Jesus really just talking about Israel anymore and the old covenant? No, it's about Christians and the gospel. He makes no mention at all about ending the old covenant. And who was He talking to? Not the Jews, but to His followers, the Christians (even though His first followers were indeed Jews).
Read it again:
Matthew 24:4 Jesus answered: “Watch out that no one deceives you. 5 For many will come in my name, claiming, ‘I am the Messiah,’ and will deceive many. 6 You will hear of wars and rumors of wars, but see to it that you are not alarmed. Such things must happen, but the end is still to come. 7 Nation will rise against nation, and kingdom against kingdom. There will be famines and earthquakes in various places. 8 All these are the beginning of birth pains.
9 “Then you will be handed over to be persecuted and put to death, and you will be hated by all nations because of me. 10 At that time many will turn away from the faith and will betray and hate each other, 11 and many false prophets will appear and deceive many people. 12 Because of the increase of wickedness, the love of most will grow cold, 13 but the one who stands firm to the end will be saved. 14 And this gospel of the kingdom will be preached in the whole world as a testimony to all nations, and then the end will come.
So yeah, no mention of the old covenant. And a few verses later Jesus tells that the end times will be the very worst, even worse that what you're referencing (since the fall).
“For all
the prophets and the law prophesied
until John.”
Matthew 11:13 KJV
“The
law and the prophets were until John:
since that time the kingdom of God is preached, and every man presseth into it.”
Luke 16:16 KJV
One covenant was broken this covenant was broken by the people
“Behold, I set before you this day a blessing and a curse; a blessing, if ye obey the commandments of the LORD your God, which I command you this day: and a curse, if ye will not obey the commandments of the LORD your God, but turn aside out of the way which I command you this day, to go after other gods, which ye have not known.”
Deuteronomy 11:26-28 KJV
The result of them breaking that covenant is it was fulfilled as the curse
“The earth also is defiled under the inhabitants thereof;
because they have transgressed the laws, changed the ordinance, broken the everlasting covenant. Therefore hath the curse devoured the earth, and they that
dwell therein are desolate: therefore the inhabitants of the earth are burned, and few men left.
Fear, and the pit, and the snare, are upon thee, O
inhabitant of the earth. The earth shall reel to and fro like a drunkard, and shall be removed like a cottage; and the transgression thereof shall be heavy upon it; and it shall fall, and not rise again.”
Isaiah 24:5-6, 17, 20 KJV
But before hat happens God promised to make a new covenant not according to the one they broke to save from that cirse they caused by breaking the covenant
a new covenant in place of the broken one not according to it
“Behold, the days come, saith the LORD, that I will make a new covenant with the house of Israel, and with the house of Judah:
not according to the covenant that I made with their fathers in the day that I took them by the hand to bring them out of the land of Egypt; which my covenant they brake, although I was an husband unto them, saith the LORD:”
Jeremiah 31:31-32 KJV
I’ll make a
new covenant with them not according to the one they broke
The old covenant was a binary choice it could be a blessing if they obeyed it all but it would surely be a curse if they didn’t if they broke his covenant Al the curses would come in fulfillment
thier salvstion from the breaking of the old covenant is the new covenant the messiah came to save them and the gentiles but israel rejected him o my a remnant received him
“And he said, It is a light thing that thou shouldest be
my servant to raise up the tribes of Jacob, and to restore the preserved of Israel: I will also give thee for a light to the Gentiles, that thou mayest be my salvation unto the end of the earth.
They shall not hunger nor thirst; neither shall the heat nor sun smite them: for he that hath mercy on them shall lead them, even by the springs of water shall he guide them. And I will make all my mountains a way, and my highways shall be exalted.”
Isaiah 49:6, 10-11 KJV
The Old Testament has been fulfilled and e gospel has been declared for salvation from the curses coming from the ot breaking of the covenant
theres a new covenant and there was an old one the old one was broken and became the curses promised in it it was never that zgod would fulfill the blessing of they broke his covenant he promised curses if they did that and they did it for centuries as he plead fornthier repentance they worshipped every god of the ancient world but for him
the worshipped golden cows and praised it for saving them from Egypt , they sacrificed thier children gods chosen to molech , they made idols of a brazen serpent and named it as a god , the built altars on all the high mountains of israel and burned incense to repham and many other gods they made the star of repham thier national symbol ect
osrwel did everything Hod told them would bring them a cirse that would destroy them but for a small remnant he would spare
“Hear ye this word which I take up against you, even a lamentation, O house of Israel. The virgin of Israel is fallen; she shall no more rise: she is forsaken upon her land; there is none to raise her up. For thus saith the Lord GOD; The city that went out by a thousand shall leave an hundred, and that which went forth by an hundred shall leave ten, to the house of Israel. For thus saith the LORD unto the house of Israel, Seek ye me, and ye shall live: but seek not Beth-el, nor enter into Gilgal, and pass not to Beer-sheba: for Gilgal shall surely go into captivity, and Beth-el shall come to nought. Seek the LORD, and ye shall live; lest he break out like fire in the house of Joseph, and devour it, and there be none to quench it in Beth-el. Ye who turn judgment to wormwood, and leave off righteousness in the earth,”
Amos 5:1-7
The Old Testament needs to be read thoroughly through it’s always a binary option they could be blessed or cursed
jerusalem could be destroyed or it could have been saved if they had received the messiah and annointed him as king they just kept rejecting everything God did and called then to sonthoer covenant was broken and the corse came that th ey were warned of but he offers salvstion by the gospel before the end to them then to gentiles
Read about the blessings and cirses of the law and you’ll see how and why the Jews have had such a terrible path for thousands of years and still are hated and despised today by so many who n the world all thoer plight is written on the mosaic law the things they e gone through is all because of the broken covenant
One could apply that to every believer that has ever lived. We all struggle with trials and temptations we fall we get up and we all endure to the end. When some fall and can't get up other believers gather around and help.. no one is lost. 
