> I wish Firefox got more varied sponsoring from multiple sources, too.

Mozilla promised that decacdes ago and yet they are still stuck with Google's money.

The problem with Firefox is that the money has to go through Mozilla, and Mozilla is not spending most of that money on Firefox. You cannot sponsor the development of Firefox directly, so your money ends up being wasted.

Firefox/Gecko also just can’t be as relevant as a Chrome/Blink competitor since Gecko doesn’t support embedding on desktop operating systems, which precludes things like Electron-style wrapping and hybrid apps. It’s a fatal flaw that Mozilla doesn’t seem to have any interest in addressing.

There is nothing wrong with using CEF/Electron for some apps and then browser-based Firefox clients for the other ones.

Big names like Slack and Spotify can’t choose to use a Gecko-based Electron/CEF alternative though, which limits its potential impact.

Maybe that's why Servo got the boot?

Unlike Gecko, Servo supports embedding as a first class feature. It was designed from the ground up with this in mind.