It absolutely sucks to have to demolish your body like a professional athlete (that gets professional athlete pay) for next to nothing. The Olympics is the pinnacle of amateur sport.
I’m sure that every Olympic athlete is “taking a loss” financially when they do the math on the hours spent training, competing, traveling, and resting vs gains from sponsors.
But, there are sports that allow athletes to have day jobs. For example, firearm and archery events, curling, etc... But, track cycling isn’t one of them.