Its about total costs. Take drag racing, which my dad does. Cost $300ish for a sportsman entry to a 5 day, end of year, no points on the line race. (Halloween classic in boise idaho) Winner gets paid after the second round. This event pulls 600+ racers and a bunch of spectators, concession, each class has a sponsor, etc…
That all adds up to a large pot of money.
where as karting doesn’t come close to 600 entrants, fewer sponsors and not many spectators, from what ive seen. The cost is then passed onto the racer bc they will pay it, they (we) dont have a choice if we want to race.
Couple that with the fact there is no true national series or leader and its that much worse.