He never said the world would end then, only that the generation that sees the sun lose its fuel and the literal death of the universe would it be the last. Matthew 24:29-30:
> And immediately after the tribulation of those days, **the sun shall be darkened and the moon shall not give her light**, and the stars shall fall from heaven, and the powers of heaven shall be moved: 30 And then shall appear the sign of the Son of man in heaven: and then **shall all tribes of the earth mourn: and they shall see the Son of man coming in the clouds of heaven** with much power and majesty.
And this would not come until after the abomination of desolation, which is the Vatican II. Matthew 24:15
> When therefore you shall see the abomination of desolation, which was spoken of by Daniel the prophet, standing in the holy place: he that readeth let him understand.
The entirety of Matthew 24 was to prevent false prophecies and misunderstandings. We still do not know when such a thing will occur but we have seen the abomination of desolation so the warning signs are beginning to show. Could be 10, 20, 100 years from now.
> And immediately after the tribulation of those days, **the sun shall be darkened and the moon shall not give her light**, and the stars shall fall from heaven, and the powers of heaven shall be moved: 30 And then shall appear the sign of the Son of man in heaven: and then **shall all tribes of the earth mourn: and they shall see the Son of man coming in the clouds of heaven** with much power and majesty.
And this would not come until after the abomination of desolation, which is the Vatican II. Matthew 24:15
> When therefore you shall see the abomination of desolation, which was spoken of by Daniel the prophet, standing in the holy place: he that readeth let him understand.
The entirety of Matthew 24 was to prevent false prophecies and misunderstandings. We still do not know when such a thing will occur but we have seen the abomination of desolation so the warning signs are beginning to show. Could be 10, 20, 100 years from now.
> Truly I tell you, this generation will certainly not pass away until all these things have happened.
Strongly implies that the second coming of Jesus would happen within a few decades.
So what Jesus predicted didn't happen.