Buying a MiST board you pays only for HW manufacturer. It's not a secret that HW manufacturer donates some boards for active developers and it's good help for those who spend a lot of time for open source projects.
But saying that some part of MiST price goes to core developers is not correct. Most developers are just doing it for free, for fun.
If you won't count the MiST board itself, then MiST project is simply open source project where anyone can participate and no one is obliged to do what he doesn't want to.
Thus complains about core quality is not correct or welcomed here.
Don't ask what MiST community should do to you, ask what you can do for community
Talking about paid cores is not correct as well because creating the core requires very precise knowledge about emulated hardware. In most cases there are no such info. Developing the core is like a science where you try to guess something or look for info by small pieces and try to solve the puzzle. And at the end you even don't know how precise it will be emulated. And if it will cost the money then only more angry people will come to complain and demand the quality for money.