Some of it is done that way, but by no means all of it. You can easily see the differences, because, say, Wes Anderson movies are not the same as Martin Scorsese movies.
If it were really all just market decisions, directors would have no influence. This is not remotely the case. Nor are they paid as though that were true.
If it were really all just market decisions, directors would have no influence. This is not remotely the case. Nor are they paid as though that were true.