Strategy doesn't work in a luck based game. In a skill based game, you also need to be lucky for you to win your bet. It's a norm that gamblers will try their possible best to come with various strategies that they feel will work for them.
No amount of strategies would save the day in most of the games in casino bettings, we should just know and admit that the house is the one cutting the shot here, you win when they want you to win. Even if your suppose-winning strategy worked for a while, it can't be long before it would start disappointing you. That time it worked might also be the time the house wanted you to win, which most people mistake for a working strategy. I only respect strategies in sports betting.
Basically when we talk about the type of casino game I think we all know that this is a type of game that depends entirely on luck, there is no strategy and no way to win, simply it all depends on how lucky you are when you play, and as you said it is true that this is the reason why many people say that the house always wins, because we are gambling under the advantage of the casino.
On the other hand, in any type of game such as sports betting, strategy is not something that guarantees victory, it is nothing more than a tool to get closer to victory but does not mean ensuring that you will win at that time. So one thing I want to say here is that before you get involved in any type of game you must understand the opportunities and risks and regarding strategy, understand that it is nothing more than a tool, nothing more than that.