The pyramids mostly take care of themselves - most of the Roman sites were destroyed because people needed stone, and its easier to get pre-quarried stuff than dig it out of the ground yourself.

Our reverence of past architecture is a pretty modern trend - and the amount of work it’d take to keep repainting and gilting these ancient buildings is unreasonable if they aren’t useful.

The materials being repurposed is pretty awesome though, it sucks to lose old buildings but being able to reconstruct where stones from a given ended up going and them receiving care and maintenance in their new homes is better than the material being outright destroyed… and it helps weave history into our everyday lives.

One interesting debate you can follow right now (ish, it’s mostly been settled) is the repatriation of totem polls that were stolen from Haida and Coastal Salish peoples… there was a debate about trying to preserve them in museums or returning them to the tribes where they’ll serve their purpose and weather away to nothing. A takeaway from this discussion is that, if you have nothing else, it’s not a bad idea to try and preserve items so that future people can appreciate them… but there are also active totem carvers alive and passing on the knowledge today - it’s better to provide funding to keep the artform alive.