Apparently for some every developer should work only for love and affection from their cardboard box and release their software as a free-for-all, but at least feature-complete before they starve, or else it gets a negative review.
Most people don't do that. Look at the donor count for Lemmy World vs DAU.
LJ (dev of Sync) has had a patreon for years. The patrons pale in comparison to the people who used Sync for Reddit, and I'm sure Lemmy as well. Patron-types are outliers among outliers.
My point about still being able to charge stands. I've seen OSS do it - if you want it quick and convenient you pay e.g. through Google Play store or official website. Yes cheapskates will compile it themselves or fork it or grab a free version from F-droid etc but they were probably going to pirate it if it was closed software anyway.
People don't like to make sacrifices today to avoid a potential disaster tomorrow. Especially when that disaster is only theoretical. (See the climate crisis.)
At work I've started taking an 'I told you so' photo of problems on the day they are identified so I can bring it up at 6 months later when it finally fails. Would recommend.