Neither do their patrons, not even the ones among them who claim to have infallible systems for predicting the outcomes of races and roulette wheel spins. So sometimes they think they're going to make a profit and they don't. The bookie does.You know about as much about the laws of probability as you do about bitcoin markets.
If what you said was true then bookies and casinos would not be able to make a profit since they never know when their patrons will win a bet.
