The entrepreneur in me will never understand this problem: "programmer creates world famous software used by Microsoft and NASA and doesn't make any money and is burning out from all the work."
Here are your solutions:
1) If the users want support, charge them for it. Split the proceeds with someone who will actually do the support. If it's still too much work, raise the price.
2) If the users want features, charge them money to put those features on your roadmap. If they're asking for features you don't want to add, just raise the price or say no until they go away.
Here is what will happen when you ask for money: people you don't want to deal with will disappear. Also you'll have more money, and you will work less.
Do you need to think about business a bit somewhere in there, sure, but probably a lot less than most people think. The "business side" for the Grunt guy could probably be "register an LLC online then get an Upwork account and let them handle the other shit like your payments and tax forms for 5%." Yes, fucking Upwork.
I don't see the non-profit model scaling to the whole industry, and the examples we have today of non-profit foundations mostly don't pay maintainers. For example, Log4j is under the Apache Foundation but none of the developers on its committee were being paid.
Apache's model is the traditional one which isn't aggressive enough. Linux foundation is more aggressive about offering lessons as products etc. I'm not as happy with LF' model as the hippie model but it is better than devolving into no new work causing no one to donate because ex-maintainers are supposed to have vesting future stock, etc.