Parents are one of the important stake holders of school/ academic institution. Their interest to their wards matter much to improve the standard of the education inculcated by the students. Therefore they must be involved in decision making procedure of the school management. PTA meting should be made in regular manner and the academic growth of the student should be within regular vigil of the school authority. There should be strict regulations for the "índifferent parent", who hardly care about this. However you can go through the attached write up.
I believe that PTA as a concept should be part of the DNA of any education. I would not limit it to meetings only. In fact, maybe meeting should be just one aspect of PTA. And maybe it Should be called; Student, Parent Teachers association – SPTA. (In this the students are the first priority.)
So perhaps what you looking for, needs to be the end result of the educational DNA called SPTA. I believe that the more the parent see that you care for the children – and not always they have the time to do it – the more they will be inclined to join these efforts to involve them and the better their children will learn.