My observation has been that the small schools take much more money per student, to educate the students. I think the smaller schools end up shortchanging the students on what they teach because of their extremely limited curriculum. For example; it is very unlikely that a school with ten students in a graduating class will have a shop class for the two or three that might be interested.
The problem in rural Montana, is bigger machinery and bigger farms result in a shrinking population. Push comes to shove when the cheapest solution would be to close the small schools and bus to the bigger ones. BUT! and it's a big but, When you close the small school, the small town dies along with it and thus, the residents seem to be OK with spending an obscene amount of money that comes from more populous districts, to keep the little school and town alive just a bit longer.