It's just feels but I've had the opposite impression:

It used to be almost no remote jobs at all. With Covid a lot of the jobs that were US only became "Remote (US only)". And over time a lot more timezone restricted ones appeared.

ed: Had Claude put together a small analysis of it: https://bewelge.github.io/whoIsHiring/

So the share of US-only remote jobs seems to have been steadily increasing as long as remote jobs have been increasing.