"Excellent" is a relative term. The average school is going to be average by definition. If you focus on excellence, you are focusing on the best-performing schools and ignoring the rest. If you are interested in the quality of the education the majority of kids are receiving, you should pay more attention to the average unexceptional schools, where most kids meet the expectations but do not excel in anything. If the expectations are too low, there is probably something wrong with the administration or the level of funding, or with the status of teaching as a profession.