I think you are misunderstanding the problem being solved. Expecting all instances to become non-profits and manage even more responsibility exacerbates the problem and inhibits the fediverse growth. Non-profits also have their share of pitfalls and is an entirely different beast.
lemm.ee told you the reason they were shutting down - not enough people to keep the place running and burnout. I can’t force you to see how minimizing and distributing responsibility helps those issues if you don’t want to. Less responsibility, easier for people not to ditch projects or end them.
That has nothing to do about what they decided to do afterwards. I thank them for not transferring the instance domain to a completely different party without user consent, and people would have disagreed with that so it’s best everyone found their own solution. It would even have put their account information at risk.
Like I said, I can’t force you to see it.
Being a dedicated content instance provider would also inherently imply dedicating that instance to a certain, more controlled type of content. An authentication instance might want to cater to a geography, which will probably decide to interact with the rest of the world and to provide adequate verification and certification mechanisms. A content instance might want to cater to a geography or a subject, resulting in specialized participation, with certification and verification based on the content, not the user.
You keep seeing monolithic instances that congregate the most communities as a plus. That’s a negative in my perspective on the fediverse. It shouldn’t be competing reddit clones with the one having the most communities winning out.