Want to know how directors make it -- after all that formal training? Like this: go to hollwood and become a p.a. (production assistant), which means fetching coffee and running personal errands. Work your way up to assistant director and talk some independent record label into letting you direct a music video. From there you can direct some commercials and then get an agent who will put you up for a low budget movie.
The indie movies are strictly for rich kids who can raise the million dollars from friends and family. When they say a movie was shot for $100,000 -- they don't count in post production etc. that can boost the price enormously. And only one out of a hundred of those films are good enough for Sundance, etc.
Look, Hollywood is a high risk, long odds profession. Those who take the risk and who have the talent are the ones who win at it. There are no assurances and if you lose, then you get to spend the rest of your life driving a limo or selling office products over the phone.
Linklater and Kevin Smith weren't rich kids from what I understand. Though you can make the case they were just lucky. Hell, Smith isn't even all that talented!