You are coming up with the assumption that the gamblers must gamble with the mentality of "winning more money or at least losing less money". I've always thought that this is a wrong mentality. Gambling is supposed to be fun, not a chore(assuming that you know when to stop and don't get addicted). To me, the mentality of gambling in order to win some money will always lead to addiction.
That's the point. It is by no means to be taken as a system for making money. The ideal is to think about entertainment. Like going to the cinema, but with the difference that at the end of the session you may leave with more money than you came in with.
<...> for me a casino that gives players more advantage is because it is in trouble, it is like banks when they advertise, and I have seen some casinos that claim to have the lowest house edge there is, and all at once I think that they are in trouble <...>
You are wrong. A lower margin attracts more customers. It does not inexorably mean that the casino is in trouble.