Positive mindset without having enough knowledge, no plans and research will just end up getting lost as normal. I don't think in any way being positive mindset help you to win in gambling, of course it will do in different things. But for a luck-based casino games, it doesnt work like that.
I agree with your opinion, it sounds quite reasonable considering the dominant strategy is only when betting on certain games, such as sports betting that we know analysis is needed here to increase the chances of winning, so not only rely on luck that plays a role here.
In other games we may have poker which almost all gamblers definitely rely on strategy to win the game, this requires focus and timeliness in making decisions, this is a recommended game.