Their 'donor' is Google, their users are us. Without us they have no donor. Rust at least makes some kind of sense because it is a tool they used to build parts of Firefox.

Aside from being the new hotness, what exactly about AI makes sense for Mozilla/Firefox to jump into and have anything to offer? The one obvious thing they could do would be to integrate AI capabilities into the browser for the users benefit (i.e. the most valuable thing they could do to contribute to 'trustworthy AI'. Note that this would not require a new foundation/company... just integrating the capability into the product they already have) But of course Mozilla most likely won't do this... they're going to keep taking moonshots they can't afford. I can't say I'll miss them when they're gone.