This is obviously incorrect: Let’s say they have to pay on each 500-play window, on true random, operator can end up with all 500 plays as non-paying and break

This is obviously incorrect: Let’s say they have to pay on each 500-play window, on true random, operator can end up with all 500 plays as non-paying and break the law. This is why they are programmed to increase payout odds if there was no payout for long time, and this is why some players wait for such machines. (In modern casinos machines are pooled, so it’s actually more complicated)