Even in the early days of the App Store on the iPhone/iPod Touch it seemed like there was so much opportunity for new types of games and experiences that could be made with the new formfactor/input method compared to prior gaming handhelds. Games like Doodlejump and Angry Birds weren't anything revolutionary, but they were at least simple little time killers you could pay a few bucks for and you got a whole experience to slowly make your way through on the train or whatever.

But it seems to model just doesn't work, or at least the cash cow turned out to be virtual casinos/gacha.

Yahtzee Croshaw did a video discussing what went wrong with mobile gaming that I thought was pretty interesting:

https://www.youtube.com/watch?v=Q30qZSEnI9Q