23:24 can be interpreted as the prophecy regarding the destruction of Jerusalem, it did fall in the lifetime of those whom he was speaking to.
Can't be...There are too many other things that didn't happen historically for that to be so...And after reading the book of Revelation, it's clear our earth is going to be pock-marked with atomic bomb craters, flattened mountain ranges, and a host of what seem to be natural disasters on a scale yet unimagined by anyone other than a bible believer...
These things 'could have happened' but they didn't...Those people ,at that time, could have accepted their Messiah in which case Jesus would have finished fulfilling those prophecies on the spot and initiated the Millennial reign 2000 years ago as prophesied thru out the Old Testament...
The OT saints were not looking for a church age...They were looking for the arrival of their Messiah who would immediately usher in the new Kingdom...
So while that narrative Jesus spoke could have applied to those at the time, it didn't...It became a future event that hasn't happened yet...