In fact, many people make quite a good living doing just that, or giving away the software and making money via imbedded means a la Firefox.

Not really. It's the cognitive dissonance of the Free Software Movement.

Software is either free or it's not free. It's either restricted or it's unrestricted. It's either proprietary or it's open.

Using hyper-capitalistic entities like Google and Facebook as a defense of the viability of free software is an interesting way to go. If anything, I'd argue they are almost perfect subversions of Free Software. Going a little deeper, a place like Y-Combinator is an even further subversion because, at it's core, it is a company that specifically exploits the profit motive of developers.

That aside, I think it's not particularly useful to argue that Stallman's contributions to the field are a vindication of his basic philosophy. Especially when those contributions are being used in a way that subverts it.