> In the games, you roll a die and have small change to receive a big payout.

This is untrue of most games with IAP. You are usually buying in-game items to speed up your progression through the game, or to give you some advantage.

In practice, I imagine the brain mechanics are much the same as a slot machine though. I once saw a senior couple sitting at McDonald's next to each other, both on an iPad, slowly tapping away at the screen of what looked like a Clash of Clans/other town builder game. The dead look on their faces as they tapped away reminded me of addicts at slot machines. While the gambling aspect isn't the same, the dopamine hits I'd say are largely identical.

Have a look at the Top Grossing free iOS games. They all rely on random drops from loot boxes (perhaps in addition to timers)

Fortunately most PC games have moved away from paying for anything that gives you an in-game advantage, and instead have moved for paying for "skins" or cosmetic items for game characters. It turns out that people care enough about this that it's a substantial revenue stream, and enables a number of widely-played games to be completely free, and playable in just as effective manner as those who spend money.

It's a similar desire to wear the latest fashion, not last year's or last decade's fashion. Art designers for these games are charged with creating new stylish character skins and effects that people would be jealous of every season. I'm perfectly fine with this as a monetization model.

One exception is Blizzard, who charges $60 for Overwatch and then also sells loot boxes with cosmetic items. There are other games like Path of Exile that are completely free (and aren't battleground PvP games) that rely entirely on money from players buying cosmetic items. (OK, to be fair Path of Exile does allow some small in-game advantages from buying stash tabs i.e. more inventory space, but it didn't feel like a huge advantage compared to the number you get by default.)