The bigger the budget, the more people that you have to coordinate and it's not easy to do that always because, not only do people have trouble communicating in that way, but often there are internal disagreements and everybody is not necessarily on the same page. Even in a big-budget movie with famous actors and directors, everybody could be on a completely different page. The director has to figure out a way of getting everybody on the same page, more or less, and keeping them there.