My understanding is in the case of lemm.ee they were getting enough donations to cover the technical operating costs, but they did not have enough high-quality volunteers for admins (and presumably not enough money to pay admins. It would require a lot of money to pay fairly for that work).
Well kind of yes and kind of no. I never closed my R account, and I still check there maybe once a week. So in that since “yes”. But on the other hand, the quality of posts and discussion is pretty low. It feels like a lot of the content there is posted to meet some goal, such as selling a product or influencing opinions - rather than just sharing thoughts and ideas. I find that pretty off-putting. Despite the very high comment counts, genuine discussion there is almost non-existent. But the one bit of value I do sometimes get is it often has some piece of niche news that I’m mildly interested in.