I agree with you, but then, I think there are some gamblers that will disagree with you on this, and tell you that there are really some strategies, patterns, tactics (call it whatever), through which slot players can enhance their winnings, and one of those strategies is the popular martingale strategy - I believe you already know what is strategy Is all about.
Though to me personally, I don't believe this to be a strategy, since it does not enhance one's chances of winning, it only enhances the pay out, this is if the player is lucky enough to win, - but then, some gamblers still see martingale as a gambling strategy, most especially, for slot games.
Obviously there are people who will not believe me but if those people really would be winning they wouldn't care what i say. In fact they would tell no one about their strategy so they could keep on winning.
Martingale working or not isn't really a matter of anyone's belief, it's
mathematically proven not to work. I personally don't mind people using it as they might as well when everything is luck based, anything goes. If you like rubbing a rabbit foot or pray to gods or look for horoscopes it's all good fun in my eyes as it's all luck. As long as they are not betting their house because they are so sure about their superstitions.
But i do get a little annoyed when i see people selling scripts for different kind of strategies and post their "proof" of winnings. That i find immoral.
First of all, I don't think that is wise to play slots using classical martingale. Doubling bet after every loss will bust your amount on any slot. I guess there's always a possibility to get a lucky hit in the first 10-20 spins, but it's stretched. I usually raise my bets after 50-100 spins, when I really wish to hit a bonus with some higher bet... which works sometimes, and sometimes not.
Martingale is more for in-house games. Where we can choose a multiplier and adjust our bets and what the bot should do after losing, winning, and a streak of wins/loses. I like to have fun with auto betting, and many strategies work for some period of time, but those who play a lot using only one strategy will run into some crazy long losing streak sooner or later. This can be avoided with some very low basic bets and "not so greedy for profit" strategies, but even after all day of playing and +500k rolls the won amount will be little, insignificant.
In the end, some kind of martingale is always present, what can we do after a long streak of losses? We can only raise the stakes and hope for a lucky hit.