Ask HN: Why aren't there many AAA Mobile game titles?

As a kid I liked to play PSP games. And there were some really high quality games on the PSP like God of War, Assassin's Creed, Mortal Kombat.

A decade plus later, smartphones are as powerful if not more powerful than PSPs.

I expected to be able to buy God of War level AAA game titles on mobile and play them on my smartphone.

Alot of games on the smartphone stores however are online games seemed to be optimized to make people buy stuff from in-app purchases.

The games on PSP were way more fun and by that I meant they had long interesting stories and clever play interaction.

I have a feeling smartphones have the ability to usher in a mobile gaming renaissance for AAA games.

But my question is, why hasn't this happened yet? All games seem so mediocre in smartphone stores.

Note that I am not saying that great games don't exist on mobile. I think my favourite game on mobile has been Monumental Valley.

But what I am talking about are games with rich game play & story telling like God of War, Assassin's Creed et Al those types seem almost non-existent on mobile I wonder why.