While this is the idealist point of view, if you earn 100K a year from open source work - and that's already the top 0.1% if not less of open source developers - and a company comes around to buy you out for $10 million plus a 300K / year job (for example)... open source etc just can't compete.

Well that is why it is open source. It doesn't matter how big the company is behind it, you can use it without the company that owns the name, and even use a different, small tech company for support.