[forgotmyoldname]

In East Asia, Japan in particular, most "old" buildings are reconstructed fairly often. They might reuse a lot of the old supplies, but many are very much a Ship of Theseus. Roman structures are, for the most part, preserved as they were--not fully disassembled and rebuilt.

One thing is that most places with extremely old structures have them far and few between. A 2000 year old building that wasn't rebuilt from the ground up is often a symbol of national pride for a country and seen as somewhat of a miracle that it's still standing. What makes Rome unique is the city alone is full of such structures, and it's a living, active city. In other countries that had a Roman presence, many of their oldest structures are remains built by Romans.

Most Egyptian structures were buried under sand for millennia and well-preserved as a consequence of that. I have to wonder how they'd hold up if they were in a different climate and with humans bustling about constantly into the modern era.

Either way, Romans were clearly doing something special.

[qwytw]

The Roman period was followed by general population contraction and a total collapse of urban centers. The city for Rome itself did not reach the population it had in the 200's AD until the early 20th century. Of most ancient Rome was an abandoned or sparsely inhabited ruin (much like many other Roman cities) which is why so many buildings survived.

If Rome had remained a densely inhabited city most of the ruins would had likely been completely destroyed and built over (besides a few temples which were converted to churches). If we look at smaller Roman cities like Cadiz, London, Paris, Milan etc. there aren't that many traces of Roman times there because their population levels eventually rebounded during middle ages.