I played piano and cello for many years, not because I was ever going to be any good, but because I loved it and because I loved playing with others. I practiced enough to play to the level that I wanted, but I didn't have the time or inclination to put in more than about 90 minutes per day at the most (well, maybe more on the weekends or just before performances!) This is very much what fanfic is to me - something that I enjoy, but not something to which I want to dedicate a tremendous amount of time and energy. In my case, I went a lot further with music theory than I did with performance (and also studied literary theory more than the craft of writing!) - I wonder if that's influencing me enjoying reading as much as or more than writing.

I absolutely agree that to improve, practice and maturity are required. It's just that it's not my highest priority. And I think that's okay, too.