The problem is you are judging quality of content. That's far down the list of criteria when Hollywood evaluates material.
First is: Will it make money? All else is secondary. The only exception is if some high-powered executive wants to make something a pet project (perhaps because it furthers an agenda he/she is passionate about, or will impress the Entertainment Elite). In that case it can get a green light even if there is no potential for making money.
For example, look at how many simply awful movies have been made with this formula: R-rated, lots of nudity, bathroom humor, profanity + low budget + one recognizable actor + plot based on young adult activities. They probably made money anyway, because there is a guaranteed audience for such movies no matter how bad they truly are.
They also care about whether the writer can deliver a filmable script. They have to be assured the writer can at least produce a work which can be brought to the screen. If the writer can't do that, there's not going to be ANY movie.
Another factor is if the writer ever had a hit. That triggers the "Who knows, lightning may strike twice" justification.
And one more factor is the industry is very insulated - outsiders are not welcome. There's no real opportunity for a non-player to even get a script read by someone who could do something with it.
It's like if you were in a fraternity and were planning a big event. No matter how lousy the members might be at putting such an event together, you aren't going to go to someone outside the frat just to have a better event. You'll just make the best of it using the people you already have.