I believe the later part of your comment to be correct, and the former part isnt very correct, when it comes to games like slots, personally, after much studying, I concluded myself that there is no strategy that can change what is destined to be the fate of a gambler playing slot games, that is, if destiny has made it a must that you will lose your money playing the game, you surely will lose that money, because when it comes to games that has everything depending chance, strategy has little to no role at all to play in determining when such a player should win or lose.
But on that other hand, strategy can be applied to the way we choose to spend our money on the game, with the right strategy we'll applied, even when it's an unlucky day, you discover that you won't lose all your money when winning is difficult, your strategy will ensure that you have an exit plan just incase things fail to go the way you planned it.
Yes games like dice, slots, are all luck based games and there is no strategy that will work for them, besides the fact that their are programmed to work that way, it important also to know that house edge on such games are highly effective and the casino make it a priority to always put the revenue at first concerned so majority's of those games goes in the favour of the casino against the gambler himself.
But mind you also the chances to win those games also are there and since it doesn't require skills to play them their winning is always a thing of high excitement.
You are absolutely correct and I completely agree with you, luck based games always come with high house edge, and this is actually the number one reason why it's always very difficult to find someone who is a constant player of luck based games that won't be in the red, by "being in the red" I mean that their over all loses is always much more than their overall winnings.
Sometimes, I feel both online and offline casinos use the fund players lost playing games like slot and the rest, to fund and pay players who are betting on sports and winning due to their vast knowledge in sports.
So, this is to say that casino use slot games and other luck based games with high house edge, as a means to raise funds for the continual running and maintaining of the casino.
But again, the last part of your comment is also true, there is still and always a chance for the player to win, but one thing that is certain for sure is that, you as a gambler can never depend on luck based games and beat the casino overtime.