I think this is, to a large extent, the problem. In commercial filmmaking you're rarely completely free to express yourself creatively. In most cases there is some degree of compromise, be it technical limitations, budget and time limitations or commonly; investor, distributor, broadcaster, marketing, legal, territorial or political requirements/constraints! In lo/no budget amateur filmmaking, most filmmakers have a particular area/s they find fun and in many respects have more time and are more free to express themselves creatively than most professional filmmakers but then lack of budget and lack of knowledge and experience means that the end product rarely works as intended or only works in parts.
I'm not saying that filmmaking isn't expressive or creative, just that in reality it's not so much about pure creativity but more about compromise and being creative within a relatively tight set of arbitrary boundaries. For those entering the professional film world expecting a high degree of creative and expressive autonomy, the reality is likely to be quite (or very) disappointing.
G