> how many embedded systems in 2024 are really RAM-limited?

A lot. Plenty embedded Linux stuff still ships with 256 MB or 512 MB RAM, and the wishlist for features in the software running on top is always getting longer than initially planned...

But of course the average has moved up, and it's not unusual to see systemd in embedded systems either (while I don't have a number at hand, the 250MB number seems off to me). The space is big, and different constraints and rules at different points in there.