Keep in mind that drivers don't just drive, they also use simulators and visualise, things which are easier on the body and allow them to memorise turn placement, timing, etc. They would also be studying different aspects of the car, learning the car's physics, learning new techniques, training their bodies, and studying telemetry.
I'll use a few examples, not racing since I don't do it. In mixed martial arts a high-level amateur will train 15-25 hours a week, and a pro will train 25-35 hours a week, approximately. 10,000 hours at 30 hours a week equals 333.33333 weeks, which is about 6.4 years. This is probably about the time it takes to get a black belt if you are skilled and dedicated, (keep in mind you would need approximately the equivalent of two black belts and a third area of expertise to fight in MMA professionally).This would also be approximately the time it takes to become completely fluent in a second language, again if you are skilled and dedicated. And you'd likely have to double that to write a book in the other language.
Unfortunately there are levels of extreme skill growth and stagnancy, you can hit walls. Just think of any sport you participate in, there are people who seem great immediately, perhaps they have some crossover from other sports/areas of knowledge; some people are slow to pick up the basics and then take off like a rocket at a certain point; and others take forever, they may never get good no matter how much time they put in. In my experience, what one person can achieve in a month may take others more than a year.
There are also levels of expertise. As we see in racing, or any other pursuit, there can be quite a lot of variance between the experts themselves. There are many who may put in as much time or more than Alonso, Hamilton, and Vettel but never get to their level.
As a further example, go (a classic board game) is arguably the most intense and difficult skill anyone could ever learn (it is also a good example since it requires intellectual, intuitive, aesthetic, logical, and scientific knowledge while also being easily studied scientifically for a competitive pursuit, which is not all that common. It is also pure skill with no luck involved, perfectly balanced, and has a very clear skill rank, which no other game/sport has; there are 30 ranks for beginners, 9 ranks for amateurs, and 9 ranks for professionals which are all very clear and objective.). Many of the professionals begin at a very young age, 3-5, and turn pro in adolescence, 11-13. They are effectively experts at this age, but there are a further 9 levels of expertise they go through which can take the top players another 8 years or so. And then they are still learning throughout their lives until their body can no longer keep up with the focus required within a game.
I would expect most race drivers would be on a similar timeline, 7 years or so to become first-level experts (pro teen/junior kart racers), and then another 7 or so to achieve a super-license. And then for another decade they can compete with other racing experts to prove who is the greatest, some will improve in this time, and others may peak or not be able to get over a wall. At this point we're talking 30,000-50,000 hours.
Purely intellectual pursuits are probably the only ones where you can increase your skill for the majority of your life. Philosophy and fiction writing for example. Then we could be talking about more than 100,000 hours.
In short, it's too generalised a theory based on experts themselves in single fields, and in no way has it been studied in terms of non-experts becoming experts. There is also huge variance between individuals, across fields, and across physical/intellectual pursuits which could further distort the numbers. Likely you will get an idea of your full potential at 10,000 hours or so, but that does not mean you're an expert. Humans aren't robots who can become experts at something based upon mechanised time, in fact, the opposite is more likely true. Often people become swept up in a pursuit, or as Senna suggested God chose him to race.
Edited by kvyatfan, 06 July 2015 - 17:09.