And for a damn good reason... Companies need money to operate. Proton may not be for profit like Google, but they are not a charity either.

Very little is free without strings, what's been normalized (in a bad way) is the concept that you can have free things that don't intrude asking for money. That only happens in the venture capital "get em hooked" stage (and we've seen a lot of it because the Internet is still relatively young). Even KDE is now asking for money (granted once a year ... but your usage of their desktop doesn't require them to run expensive servers).