If it was possible that strategy generates constant income in gambling, I think lots of casinos would have closed their doors already. The whole point is that the casino has an edge and they do so in most cases. There are of course players that are more successful than others, but in aggregate I think there would be no strategy that everyone can equally apply and win.
And by the way if someone had such a strategy, I doubt that the person would be willing to share it publicly. It would make most sense for anyone to exploit it until the masses find out about it and exploit it to the extent that bookies could respond.
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.