I think the 10,000 hours idea is probably attractive to people drawn to the structured music school/ university learning system and certainly practice involving thought and effort will produce better results, in any field.
I'm pretty sure everyone has known someone in their lifetime who just seems to find things, or a particular thing, easy. The kid at little league who seems to progress quicker than every other kid, the kid who picks things up faster than everyone else.
There are plenty of skilled and innovative musicians who seemed to go from novice to outstanding very quickly, some people just seem to be wired for certain things way more than the average. Jimi Hendrix got a guitar at age 15 in 1961, by 1966 Chas Chandler has signed him and brought him to England and by 1967 he released his first smash hit album and redefined electric guitar playing. Eric Clapton got a guitar at 13 but it was so bad he gave up and started again at 15, by 16 he was playing in bands and at 18 joined The Yardbirds. Geddy Lee got an acoustic guitar at 14, was part of Rush by 17 and by the time he was 20, Rush were a full time professional band
doing their own material. Chris Squire took up bass at age 16 inspired to play music due to The Beatles, because he was tall a friend suggested the bass. Within 4 years he was part of Yes aged 20.
I don't know how many hours of practice and playing people like these squeezed into the few years between starting to play and becoming the musicians they are famous for being and they probably wouldn't have known either, not that it matters. Maybe none of those players could sit down in a studio and play from sheet music and they might struggle to play a set with jazz experts, but drive, innate ability and an innovative mind is surely what makes the difference between the majority of us and the ones who innovate and break new ground.
Depressing as it is for most of us, some people are just wired for it. Even Jaco, the player most often held aloft as the master here on Talkbass and the most mentioned, owes most of his bass god status to his mind and creativity, more that his undoubtedly massive amount of practice and playing time, as plenty of jazz bass players could probably point to more hours on the clock, but didn't come up with the ideas Jaco came up with.
Well that's my two cents worth anyway.