On one side, the dominant consumer society we live in is extremely busy churning through anything that can be sold as a product and then thrown away so that the new can replace them. Buildings go up as quickly as they come down, and we digitize books just to destroy them in pursuit of productivity gains we may or may not ever get. And of course, conflicts and war continue to destroy priceless artefacts, like they've always done.

On the other side, when you consider objective metrics, I don't think humanity ever spent so much effort and resources into preserving the past as today. Archaeology was basically invented less than 250 years ago, and now it's everywhere and continuously expanding. A lot of places are now not even allowed to change, museums are plentiful and overflowing, and the internet created a completely new world of human creation that we are increasingly trying to preserve (IA etc).

It's a mixed picture.