This "Son thing" is not happening only in motorsport.
Same for many other sports. It could have something to do with what is discussed around the kitchen table day in and day out.
You will automatically pick up a lot of info, to make your understanding of the sport down to the details very different than in a home where no one habe a clue on what you are training to become good in.

Think of a dinner in the Solberg home, compared to a boy or girl asking his/her parents on something regarding their sport, that they have no clue on. The answers will be dramaticaly different, and same with the kids output. This happens every day for many years, and also being at rallies picking up details of driver talk and discussion on set-up, driving, tyres and so on, and so on.

But as said here, your upbringing will only get you so far, then you will have to deliver on your own. And in the car you are on your own making your own desicions every second. Then it is more and more training, and the 10 000 hours it takes to reach the top in every sport, as a rule of thumb.

So even if you are a "rich brat", there is something in here money cant buy, to become world champion in rally.
As we saw in F1 a couple of weeks ago, when a driver took Hamiltons car for a race and led the race and could have won, if not Mercedes had fuc..... up. That will never happen in rally!