Just found out my neighbor is a successful racer in the national ferrari series. Won some nationals, in the news, etc.
Asked him how that works, what the sponsors pay for, how much the dealerships are contributing, etc...
His answer was very interesting... "The cash only flows one way
"
Sounds like he does it because he loves it, and can afford it.
To answer your question, in order to get into racing on a national level, you had better be very wealth to start with...