The racers in question are actually motorcycles, Aprilias in the 1000cc to 50cc classes. Rotax v-twins and the like. But still fuel injected gas engines. Your dismissing of low octane fuel as something that 'cheap cars' use shows that you still don't fully understand the octane/engine design relationship.
Like mentioned, there is more to octane choice than just compression. Again, expensive /= good. If your car requires high octane, then it requires it, but just being an expensive or fast car doesn't mean it requires expensive gas.
I'd suggest, as an experiment, putting a tankful of that 103 into your car. I'm betting it will run very poorly. Because, as I said, expensive does not mean good, just different. The higher cost isn't because there is more power to be had, just because of supply and demand, less of it is needed, so less of it is made, so it costs more. Also, there are a lot of suckers out there who can be convinced to buy premium even if their vehicle doesn't need it, just by making it seem 'fancier'.
"That f***in' biodiesel is makin' me hungry."
1982 300TD Astral Silver w/ 250k (BIO BNZ)
2001 Aprilia SR50 Corsa Red w/ 5.5k (>100 MPG)