I think an important point is being missed here.
I think maybe 2d is missing it. No offence.
When I first started the piano, I completed 5 grades in 2 years...and I knew a couple people who would be playing for at least 4-5 years who couldn't get past grade 2. I'd also be composing music on the piano while these two people couldn't get past "hot crossed buns."
Point - Just because somone's playing longer than someone else doesn't mean they'll be better.
Also, look at what someone like Hendrix did? He is NOT the most technical guitarist there was...and I'd think that can be pretty much proven. Maybe though he would've been if he lived longer. But I'd say he's outclassed almost every popular guitarist in his innovation, imagination, and emotion playing the guitar.
Point - Someone could paractice for a hundred years and never match that. Casuse if they don't got it, they don't got it.
But people don't want to accept that because it might make them feel inferior or something...silly. That whole "you can do anything if you put your mind to it" stuff is just BS to make people feel that they're no less equal than anyone else. That's just not true.
EDIT: It's true they're equal in a "worth" sense, not in an "ability" sense