People have rightly said that their executives are overpaid. However it’s unclear what revenue streams they have. In terms of user services they sell a VPN. I think that’s about it. That’s not going to cut it even if they do lay off tons of people.
Browsers are complicated pieces of software and there needs to be a lot of money behind them if they’re going to succeed.
I looked into this because I thought that you must be missing something, but yes, you are correct.
Both the F-Droid package as well as the one on the Proton’s GitHub page do not allow for guest logins. This is curious. Perhaps the guest account option requires some sort of non-free library? I’d be interested in the answer to your question.