The usual model for OSS projects is that initially they are written for free. Then an inner circle forms and exploits the second generation of idealists who write entire large features without ever getting the same rights.

Some of the inner circle move to corporations to increase their power and are joined by corporate developers (sometimes their bosses) to take over the project.

A lot of corporate OSS development are entirely unnecessary rewrites or simple things like release management. So I'd put the number of useful code by employees much lower.

But governed, hell yeah, I agree. The corporations crack the whip and oppress real contributors.