I wonder if there will come a time when society decides it's better to fix ruins such as the Colosseum and the pyramids instead of letting them just rot away.
About 150 years after it was built, it was partially destroyed by fire. And rebuilt. Another 200 years later there are inscriptions from late emperors who did more repair work. In the medieval era it was stripped of marble and suffered serious damage from an earthquake. In the 18th century it seems the Popes started to appreciate that it was historically significant, and various repairs and preservation activities have gone on ever since. One of the largest cleanings and repairs ever has just started in the last decade.
How much to repair though? At a certain point you have to start taking out original work to replace the ruined interior, and I can understand the extreme reluctance to do that.
As to the Pyramids, they've been rotting for 4300 years and they're still there mostly intact. The most severe damage was intentional acts in relatively recent history. As long as we don't decide to start tearing them down again for free stone, they'll probably outlast humanity.
And especially, over time, you can end up with a bit of a ship of theseus.
Also interesting -- if some day one of the earthquakes there knocks down part of the colosseum, will we rebuild the ruins to their ruinous state?