Define what the number of people in the average “small community”.
Define “Reasonable monthly/annual fee”.
Define what would be the cut-off point to “can’t afford to pay”.
The reason that I am asking you to be specific is that there is a good chance that professional providers can be more efficient than any “community-based” solution. We can have hundreds/thousands of independent professional service providers, each serving around 100-500k people, which would make a sustainable and healthy market. On the other hand, I sincerely doubt that we would be able to serve the 2 billion people on e.g Instagram by having millions of “community based” instances of Pixelfed.