How do you expect to afford paying the [big name] actors that you sport in your screenplays?
PrevNode LinkNextFirst of all, note that I believe by observation that most of them are modern-day geeks and "amateurs" (= workers who work for fun/"love") and often agreed to act in films they liked for a relatively small pay. For instance, according to the wikipedia article about Emma Watson the one about Kirsten Dunst, and the one about Keira Knightley they all played in some independent films, which I presume paid less than "major motion pictures".
Secondly, my cast pages (e.g: 1; 2; ) are merely guidelines. Film makers are welcome to take them in their own direction (or the screenplays themselves).