Hmm it seems to me a viable solution (at least for the more tech inclined) is to just firewall it so it's unable to call home (although then there's an extension sourcing issue). Unless there's more of a philosophical stance. Or am I missing something else?

I've been a mostly happy Firefox user since v2, and have made it through - though will never forget - the extensions system "upgrade" debacle and more. As long as I have means to maintain reasonable control, I'll continue with it into the foreseeable future, because I consider the Chromium-based alternatives to be worse.