That’s quite an interesting topic!
I think I would frame a bit differently your concerns. The first thing is to differentiate: are you talking about governance or are you talking about data?
There were some attempts, from big companies, to control the foundation (employees trying to run for the board, for example). It didn’t work out well, and in the big picture, they 100% gave up on that (see the millions they paid and are paying to create/maintain Overture), at least on the short term. Regarding the data, while I dislike ODbL, I don’t see how one can “own” the data, due to the licensing terms. The data is “free”, so anyone can use that.
What I see is, while you don’t need to pay to use the data, you kinda have to pay to truly use it. OSM does not offer an easy way to professionally use the data, so you have to rely on external services for that. Also, OSM doesn’t offer “clean” snapshots of data, so, again, you have to rely on external services for that (think of that free Facebook service that I forgot the name, which is now inside Overture). Overture itself is an attempt for that: provide an easy and reliable way to ingest data.
So, answering your questions in a broad way, I would say: relax, they don’t really care about us anymore. They are happy with the free labor (they pay some people too to fix/improve the data), and that’s it.
The question is: after knowing all of this, are YOU happy with that? If yes, just keep mapping, don’t question yourself that much, and you’ll be fine.
(regarding your 4 specific questions, I am more concerned about some people inside OSM community than from big tech. They are the ones shaping OSM priorities and profiting from that, and you didn’t even notice that.)