dcstudio - thank you so much for your very detailed post. It really gives me a picture of where you're coming from. It also gives a good starting point for some real dialogue - a back and forth of ideas, possibly.
For me, it was the combination of efficient training from a very young age and my obsessive desire to master pieces that were above my level. I also used the piano as a means of escape. Then in college I totally focused on the academic side of music because I felt so inferior as a pianist. This was more instrumental than anything I believe. I figured that if I couldn't out play them I would out GPA them... and I did. lol. It was more than just having good grades though... I really studied until I understood it all and when I did finally start doing this for a living it showed.
An interesting thing about the last bit is how the academic side switched on you. Originally studying theory was a way you could do something where you could shine, but later because you had studied these things so thoroughly, they became tools for your playing. At that point you were no longer interested in shining, but in how this served your music making.
For me, it was the combination of efficient training from a very young age and my obsessive desire to master pieces that were above my level. I also used the piano as a means of escape.
An important thing I'm noting here is that two things were there a) efficient training at the onset b) what you wanted to do with music. Now imagine if had not had the training that gave you the means of producing the music that you wanted to produce, and you only had the desire, i.e. the efficient training was absent. Then a couple of things can happen. You might struggle and not manage, or you might think you're playing the advanced music but can't hear the weaknesses that your lack of skill has left you with in which case you're still happy. Or if you have a few musical bones and the ears to go with it, you might be constantly disappointed in what you can't produce - which you can't produce merely because of the lack of skills. So these two things are important.
When I was a child, I self-taught piano, and I was quite happy with it. When I was an adult, I took up an instrument that is characterized as technically very difficult, doing the right thing by starting it with a teacher. And here this issue of good and continual training in skills came up. I had a bad instrument which harmed that part, and wasn't told until almost a year went by, and I was also rushed through grade levels. The result was that eventually I was struggling with challenging material slated as grades 6 and 7, where forcing it through and willpower no longer cut it. Having a good ear and using your feelings to play led, among other things, to injury.
One reason this came about, is that my teacher was a veteran who knew that (older) students found doing the work for technique to be intimidating, and wanted to "advance" fast to interesting advanced material. This fuels self-esteem; you "are" no longer a beginner etc. You can play selected advanced material in a more primitive amateurish manner which is good enough for many. But as soon as you don't have much in the way of skills - I don't have to finish that sentence.
At some point in those struggles I literally turned my back on the "interesting" music in the middle of a practice session. I went after whatever technical issue was at hand, and went back and back until I got to a fundamental skill that was missing. I practised the skill: I found etudes - I did the "boring" work that my teacher had spared me. And when I played the piece a week later, suddenly I sounded fantastic, and it was easy to play, because I had the skill, and was not struggling.
This was my turning point. Working directly on a skill had the end result of being able to play with greater ease and sounding better. I then had a great desire to do the very things my teacher had spared me of: get basic solid skills, and even, to work on more basic material in order to get it.
This whole formula of "efficient training" (skills) plus desire is a tricky one, because knowing how to give a student skills without losing the student is both a science and an art. There are oppressive, dogmatic teachers who think they're giving skills but are simply doing what their own teachers did - others who have some magic narrow formula that works for some, sometimes, and other variants. Then there is the willingness of the student to do the work.
You have written about two things, and I will make two separate posts since this is already too long.
Topic: Our son wants to quit piano, what should I do?