Read a good article today about why some people are almost always sucessful. It lists some key traits that successful people have. I feel that I am strong on most of those points.
My martial arts training helps with some of them too like “They do things even when they don’t feel like it”. I think that some people just want to do all the fun bits of making games and then when it comes to the boring bits they just don’t do them and so their game is never finished, or if they do finish it, they don’t do any marketing and so it never sells.