Odds of Getting In
Might as well tell you, nobody in the theatre wants to hear your ideas, because they're too busy telling you theirs. But if you do actually have what it takes (determination, a pretty blatant sense of narcissism, and the loudest voice in the room), there are a few opportunities.
Starting off, you could get financing for your own show, whether by receiving an art grant, getting a gig at a university, or asking some of your friends really nicely. This takes at least a Level 9 Charisma stat, not to mention a severe amount of socializing.
Or, you could start your career in the theatre by doing something else entirely, and work your theatrical butt off until you earn that director's chair. Stage management, art direction, and even acting have their in-roads, but that does mean you'll have to listen to some other director for a while.
Of course, being a successful director also depends on how you measure it. (If at first you don't succeed, redefine success.) Thousands of high schools and community theatres hire directors. You may not get that fancy loft in Soho, but hey, it's work.