Last year there was a hobbyist race on my local track and the person who won it was a guy who mainly practices at home on his computer. I imagine a gokart simulation is close enough to the real deal that training on it actually can help a lot. You can get much more fine-grained feedback on how well you're taking certain corners etc. One thing that trips me up is understanding the kart - my local ones have somewhat poor acceleration, so it seems it's not actually best to take the corners as sharp as possible and try to accelerate out of the corner, but instead try to maintain as much speed as possible going into the corner, even if you end up on a bad line. This would be easy to test in a simulation, but I just have to go by gut feeling.
The 2nd rule we've learned is : no skidding, never. That's really hard to do. But look at top pilots, they don't skid.
The 3d rule is : you do your best time on every single lap (super good pilots do almost the same time on most of their laps, within 0.3 sec range; it's hard to believe they do it, but they do !).
4th rule : figure out the best trajectory. According to my kid's teacher it's a question of 10 centimeters here or there (good luck figuring that out !).
Strangely, passing a car is the last thing you learn. But in retrospect,it's normal : most of the time you run after the one in front of you. The opportunities to pass another pilot are rare (most of the time you're much faster so the blue flags forces them to let you pass).
As a dad, I'd say : find a good teacher, it makes a big difference.
Because that's F1. There's not a balance driver/car. There are good cars, average cars and poor cars, almost all of them driven by good drivers. In karting (and many formula cathegories) the reverse scenario is true: there are good drivers, average drivers and bad drivers, all driving similar karts.
Indoor kart racing is, in my country, affordable to, say 50% of population (you may have to make some choices though). Count +/-120€ per month (2 training session + 1 race). Swimming lessons are 30€ per month I'd say.
Outdoor karting is really expensive and is for the 1% (which I'm not part of :-)). Count 1000€ per race, gasp !
F1 is well, for ultra rich :-) Plan robbing 1 bank, or 10 (binary joke intended).
But according to many, indoor karts makes you a great pilot because the machine doesn't compensate for your failures.
* Hamilton/Verstappen in a Williams?
* Antonio Giovinazzi in a Mercedes?
Don't forget the classic "to finish first, you first have to finish"...a drivers skill is not just better reaction time or better peripheral vision, it's also mental calm, not making stupid mistakes on lap 69 of 70, situational awareness etc.
So I think that 10% is a lot of skill and dedication, but also a sort of numbing to that fear.
I've occasionally gone into a corner way faster than I should with my abilities, frightened myself, but the car has stuck to the track. It made the corner. I couldn't do this intentionally, even knowing that I can throw it into the corner x mph faster than I'm comfortable with and I will come out the other end pointing in the right direction, I still can't do it.
Then you realise that if I gave my car to a racing driver, he would drive it like that in every corner of every lap. Because he has to, because if he doesn't he's giving away time.
It blows my mind.
My limit for how fast I can drive a car is so much lower than even an average road cars physical limits.