That's fine, they should leave it at that and do it the best they can because that is presumably their competency.
But they can't help themselves and insist on engaging various other political endeavors which they just aren't good at but probably sounds good when they brag about it to their friends at dinner parties. Like operating 'online spaces' for African lesbian women in tech or whatever the heck they're calling it, which amounts to them somehow blowing millions of dollars to host a mastadon instance, which isn't needed by anybody because all the marginalized groups they claim to be serving already have online spaces of their own on Facebook, discord, etc.
That would be an improvement. Being a browser developer does not factor in anything they focus on.
Given your experience, If one were to fork Firefox entirely from Mozilla, very loosely, if one were a non-profit dedicated to just the browser and not trying to build a diversified company around it, what type of funding do you think an org would need to keep up with web technology changes and build a foundational engineering team?
Mind you, our idea was to build a "browser-based OS", which meant at the time that our initial design was customize Ubuntu to the point that it could boot straight into a single-user windowless Firefox and to build all the "shell" as extensions. (I wrote a bit about on https://raphael.lullis.net/thinking-heads-are-not-in-the-clo...)
If Mozilla tried to address this, I think many Chromium-based browsers today would at least try the possibility to be Gecko-based.
This is factually incorrect, the worst kind of incorrect. Brave Browser was initially built on Graphene, which uses Gecko. They then switched to Electron because Graphene was too raw, and from there to Chromium. Also, Brave contributes basically nothing to Chromium, so why would you think they would contribute anything to Gecko?