[moz23]

Ambitious in a technical sense - yes. But not ambitious in a "protect the users" sense (see e.g. tracking protection/ad blocking), and also not ambitious in a business sense (i.e. try to do something beyond sell users/traffic to the highest bidding search engine).

(Perhaps they could have made money by selling devices with the OS, but that didn't seem to be the aim there, as far as devices being only sold by partners.)

This is very much the stereotypical engineer approach: trying to engineer your way into revenue. Yes you need strong technology to keep users, but there's a lot more to business than the tech stack and quality.