Should be fairly easy to explain. Most private schools fall into the 2A or 3A classes. When team sports are not classed, those relatively small schools are competing against teams from much larger schools with many more athletes to choose from. I am from Evansville and in Evansville we have 2 private schools, Evansville Memorial and Evansville Mater Dei. Memorial is 3A (about 800 students) and Mater Dei is 2A (about 500 students) in football, it shouldn't be that difficult for you to figure out why they have a hard time competing with schools that have 2,000, 3,000 and 4,000 students. Are you really that dense?