I’ve got well over 10,000 hours in, but not sure I buy Gladwell’s mastery formula.
I remember about 10-15 years ago I had a chance to talk to Kenny Barron back stage before a solo concert here. He is one of my jazz idols and I had spent many hours listening to his solo Maybeck series recording back when I was a pianist, and from that considered him one of the greatest living solo jazz players. I noticed that he had been playing a lot of solo concerts lately and asked him why he hadn’t been playing trio. He told me that he had gone back and listened to the Maybeck recording didn’t like the way he sounded, so he decided to book an bunch of solo shows in an attempt to get better at solo playing. My jaw pretty much hit the floor.
So, I would say that “mastery” is pretty subjective. I know I sure as hell don’t feel like a “master”, especially when compared to someone like Barron. And if he doesn’t feel like a master…