Many schools had muggle subjects, but they never went into detail with the muggle electives like Hogwarts. For that reason, they started to install those electives in their schools. It improved the educational standards. The wards were not an issue for the schools since the headmasters and mistresses were able to change the older wards to the newer wards. In Hogwarts it was difficult since you needed all the founders’ heirs and their magic to change the wards around the old castle and the castle would fall apart, if the wards were changed since they were connected to the school’s walls. That was the reason why the other buildings were needed.