I'd be pretty certain that the fashion for bigger schools it is mainly about money. The excuse is always that bigger schools make it possible to have a wider range of subjects and teachers with expertise in those subjects.

It seems to me that is nonsense - there is nothing in that way that a big school can provide that a small school couldn't, now we have access to the expertise of the whole world via computers.

A few posts ago I pointed out that there are schools where bullying does not seem to happen, and speculated about the factors involved, I would be pretty certain that size of school would be a very significant factor. "Small is Beautiful" is a pretty good rule of thumb.