As stated in the article, trying to apply the 10000h rule to other fields is problematic at best. In chess there is basically no physical limit on how much you can study and practice. The number is going to be much lower for motor sports.
Drivers who make it to F1 have reached the equivalent of chess master level in their karting days. How many hours of seat time do they get in 10-15 years of karting?
Imaginary training is very important in sports where you are limited on how much you can practice in the flesh. How many hours is that?
I would guess the kids these days use simulators. It counts for something even if they don't have better than iRacing. In theory you could sim all day every day, but at some point there would be diminishing returns on how applicable it is on track?