“Also didn’t you say 90%+ of options expire worthless? How would that happen as a zero sum game? Every dollar gained is a dollar lost, right? does money disappear, or is it actually 50%?”

It is a zero-sum game, even if most options expire worthless. The catch is that the 10% of options that make money usually make A LOT of money, to compensate for the 90% that lose. Think of it like a slot machine that 9 times out of 10 eats your dollar, and one time out of ten gives you $10 back.