My primary argument against any attempt to keep donations as the main model of funding: everyone talks about the fediverse “being like email”, but we don’t hear of “donation-based” email providers, do we?
At the end of the day, hosting a Mastodon, Matrix or Lemmy server is work, perhaps even more work than hosting an email service. I don’t think it is fair to try to get service providers to put up these servers online and then try to find a way for them to support themselves. To me this feels like asking a photographer to “work for exposure”. Unfortunately, Big Tech and VC-funded companies flipped this around and convinced users that these services should be all like this, but the reality is that this kills independent software developers and service providers.