are you saying that the players can't get lucky and win? on multiple occasions i leave the casino with hundred and sometimes thousands in winnings. you can easily win despite house edge.
Players do get lucky and they win, but they don't stop. Instead they push their luck and more often than not they loose everything. Today you may win and get out of the casino with money, but tomorrow you will come back and loose all you won previous day, and a bit extra. Casinos count on human greed, they don't have to rig anything.
There are some that are able to control themselves, have a plan and stick to it, but those are professional gamblers and they are extremely rare.