I agree with all that you've said, if everyone is lucky then everyone would have become a millionaire in expense of casino's lose and money.
But that's not how it goes and we know that they're a business that should make more money. If the house allows some huge wins, it's already part of their expense that they'll recover easily from the other gamblers they have.
The impossible thing is that everyone is lucky enough to get a big win through the gambling they do, because if that happens then there will be a few cases of bad impacts from gambling circulating but the reality is that there are many cases that occur about people who experience bad impacts from gambling and that is because they are unlucky in their gambling but force themselves to get a win or in other words they are chasing luck which actually does not have to be done.
The house that always gets more wins than losses will certainly occasionally give big wins to its players and that is the goal is to keep them in their casino or stay in their casino if they gamble, but even so they will not experience losses because the wins obtained by the players are a small part of the profits they get.
That is normal for the house to give some wins to some gamblers, big and small.
Because if there are no gamblers that wins from them, most of the gamblers will flee from them and they're going to stop visiting them.
So, any strategy that works, it will work shortly but not in the long run.