In terms of decision making, Rust is definitely a community oriented project, but there's not denying reality and at present practically all of Rust core devs who work on it full-time are paid by Mozilla.

Were Mozilla to pull out support, development would likely continue, but at a much, much reduced pace.

> a major beneficiary of those 500 million

I agree with you that the vast majority of it is not going to Rust and I do wish they'd increase the share of their revenue that goes to engineering from 45% to something closer to 85%.