Yes, race promoters have costs to cover (rent, insurance, personnel, power, etc. etc.) but they've got to be smart how they get that money. Racers have too many choices about where to race, and even if to race... fans have even more choices and fewer vested interests... so promoters can't get too greedy. My experience shows that you'll make more money overall if you try to get it in small chunks than big chunks - more people will pay those small chunks.
I talked to the owner/promoter of a well-known and established car track near me. He was complaining about low attendance, and I couldn't blame him - both his pits and stands were pretty empty. But he also charges more to get through both the pit and fan gates than any other track around. One night per season he has Ladies Night - lets them in for half price. Not only almost fills his stands but also sells a lot more concessions, and gets some more cars too. He even admitted that it is usually one of his best profit nights. But he can't follow the reasoning that if he lowered his gate fees he'd probably see those bigger crowds more often.
Kart tracks usually only draw fans who know people racing there. Most kart tracks aren't even well equipped to handle the general public. If the track owner/promoter is going to limit his customers to racers and whomever they bring with them, he'd better get smart about how much his racers are willing to pay. I know several racers who have quit going to money races, let alone series races, even to watch - too expensive. Maybe it's something you ought to experience... but at those prices often once is enough.
