I don't know about all of these theories, but I know that you have to practice like crazy.
Some become nice (as in very good) within a year, sometimes within months. It depends on your IQ, aptitude, and work ethic.
DJ Premier became nice in producing Hip-Hop beats only within a few months and became better as time had gone on.
Sometimes, in order to see how well of a producer you are, try to get your beat or production mastered so that you can really
see how it sounds in the professional realm of digital, analogue, or hybrid audio environment.
Just be tenacious in dusting yourself off and trying again. Everybody fails in the beginning. The sooner you realize that you suck, the sooner
you'll realize the symptom in order to become the creme de la creme of the best!!!