they ain't doing it for us, they're doing it for themselves.

They've been doing useful engineering things since the start, it's just that it pales in comparison to all the bad things

Whenever big tech companies like Meta do useful things like support Overture Maps Foundation (which is also supported by Microsoft and Amazon) they are doing it to blunt some competitive advantage another tech company has, such as google in this case. They support open source insofar as they can't monetize whatever they are open sourcing.

ZSTD and BYRFS, among many other smaller things, hello?

This is very true, cheap RAM and storage just lead to inefficient, bloated code.

So using the back of a knife to cut something is not more efficient than using the sharp side? I would say making better use of hardware is also an efficiency gain. You use the same hardware to do more, while not driving up cost significantly. That is efficiency in my book.