When did this transition happen? I have tried to play but found that even after four or five years it was difficult, required a lot of concentration, and gave me little pleasure.
The only physical skill I have that might be comparable is typing, but (as a programmer) even after typing for over 40 years, while I can type without "thinking" about where the keys are, I can usually type only three or four words without needing to make a correction.
Probably not until the 12 year mark. Maybe a little before that. I would say that it was a combination of time + actively learning certain skills. There were periods where I rested on my laurels for a few years so I probably could have reduced the time by a few years (if that was the aim). I would say 7 years is around where it got really enjoyable though and I knew enough that it wasn't too much effort to learn new songs and skills.
Worth mentioning I started when I was a kid. Learning something when you're young is so much easier due to the available time and the ability to obsess (this was also pre-internet mostly). When I try learning new instruments these days it takes much longer because I have responsibilities.
I try to play guitar. For simple songs, I can play them without thinking about it. My fingers just find the next chord, almost like driving a car and not remembering the last minute of driving. For more complex things, I have to think.
So may it really is about the journey, and any learning is good learning.
The only physical skill I have that might be comparable is typing, but (as a programmer) even after typing for over 40 years, while I can type without "thinking" about where the keys are, I can usually type only three or four words without needing to make a correction.