I do some volunteer time on a small web forum, and we have subscription options on there. It pays for server costs reasonably fine, if not dev time for new features or anything. Users come from lots of places around the world, although the discussion is still mostly in English. It is optional, but the number of power users willing to pay for it covers the rest. You could also look at SomethingAwful as a reasonable strategy?

If people love a community and like spending time on it, they'll be willing to help keep it running and avoid shutting down. You don't get any real profit, but do you need that to run a website? And if people don't love it enough to pay for it, you do have to wonder if it really needs to exist.

I think Reddit could get away with their reddit pro and paying for awards deal, honestly. They would need to rely more on volunteer labor and volunteer development, but a site could exist like that. I assume it's how Lemmy and Lobsters run?