I raced motocross too and even though that was the "Cheapest" of the motorycycle sports.. it was still a ton.. 2 bikes (practice and race bike), constant top ends, clutches etc, race fuel.. travel to race, hotel, etc etc etc.. and the contingency offered by the manufacturers was crap.. plus you had to do really well to get any money that way. I agree the pro guys made good cash, but not compared to race car drivers or even motogp guys.. but back to bodybuilding, it really is pretty cheap, unless you get into competitive bodybuilding, but even then, in a year I spend less than I did on moto.
Look at its this way.. its cheaper than the cost of leaving a burning jaguar in the desert with a body in the trunk