Been racing myself since the 1960s. Have raced cars, boats, motorcycles, and airplanes ... both full scale and RC. Believe me, racing RC airplanes is as competitive as racing anything else. Don't race much anymore, but I still go out and do a track day in my 6-speed Ford Mustang once in awhile. You know, push it to about 90% and don't hit anything type stuff. Road racing doesn't eat up engine parts like drag racing, but it DOES eat up tires, brakes, and water pumps pretty well. If I do 3 days of 4 hours per day on a track, I can easily eat up 4 sets of tires, 3 sets of brake, and 2 water pumps. That assumes nothing serious goes wrong.
About the most unforgiving type racing I ever did was boats. A mistake hurts, physically and financially. Water is pretty hard at 75 mph+. And from first-hand experience, it doesn't take much to make that mistake.