How are we going to pay for all this?

I'm really enjoying lemmy. I think we've got some growing pains in UI/UX and we're missing some key features (like community migration and actual redundancy). But how are we going to collectively pay for this? I saw an (unverified) post that Reddit received 400M dollars from ads last year. Lemmy isn't going to be free. Can someone with actual server experience chime in with some back of the napkin math on how expensive it would be if everyone migrated from Reddit?