I'm using Hanlon's razor.

I think "let's rewrite in rust" is almost always a horrible idea. It's like reinstalling a server if it does not work. Feels clean, but you waste lots of time for purity. Fixing bugs is hard work.

But it's a huge code base so what do I know.

I don't think it's sabotage from Chrome team, Google needs Firefox because of as antitrust/ anti monopoly.

I think it's just not interesting enough for devs and to be fair, both chromium and webkit based browsers are good.