Squeak:
Assuming no mortgage (owned or borrowed building), elementry school, one teacher, and no scholarships your numbers could work for a lower tier school (depending on insurance and legal compliance costs). But those who could pay more would want more (smaller classes, air conditioning, heat, projects and trips, gym, etc) which would create adverse selection to the others who can’t pay.
By community school, I did not mean community FUNDED. I mean similar to my previous idea, that the schools can send their scholarship children to a lower cost school (such as the one you describe), thereby saving in total costs to educate ALL children.
Besides, all of us are obviously OK enough with the status quo that we are not running our own school.