Yes, this happens in every casino, in particular I am a very active casino player, but I always look for a way that when I play slots I don't want to win, why? because I am sure that this is for fun, of course there are very determined players who if they seek to win and make very large bets, in the threads of stake.com and in others such as bitcasino.io there are always winners who proudly publish their winnings and apart the gains are very large, I would say that some win in a stratospheric way.
They published their winning side but if you take a closer look, they didn't bother to share the losing side, for sure there are many gamblers who manage to win decently with slot some lucky day that allow them to multiply there bankroll but long term wise the outcome always in favor of the house, we can't change the fact that casino always have house edge to take advantage and the longer the gambler will play the chance that he will lose everything.
You're right, they only show us the tip of the Iceberg, all the effort there is to get there because they don't sample it, maybe it's a very long history, full of losses, it's something normal,if I get enough of a history of Losses, but it's normal, when I play slots I don't want to win but to hang out, have fun, it's like going to a fútbol stadium, where I enter another environment that I enjoy, so that's how I see slots, That's why I really admire when they buy those profits, because the bets that make wow, unless I were a very millionaire is the only way I would do it,otherwise I don't have the capacity to do something like that