I don’t understand who is the target audience for AAA-gaming on smartphones. There are few million people buying those games on PC and Game Consoles, which are usually devices dedicated for gaming. On iPhone, I doubt that Resident Evil games combined sold more than a 5-digit number. Also, there were Resident Evil games on iPhone before, like Resident Evil 4. Guess what? You cannot play it now, because the app was never updated for the modern iOS and Apple dropped its support.
Current iPhones can be used as game consoles by hooking them up via usb-c -> hdmi to a TV and pairing a controller. iPad's make great gaming devices due to the larger screens. With a common architecture is easier than ever to just bring the game to all iPhone/iPad/Macs, besides, there are ten times more iPhones out there than there are Nintendo Switches, so if just a tenth of iPhone users game it's still a sizable market to address.