At this point ios/android are nearly as standardized and ubiquitous as TVs were when home consoles started to boom. The 'console', then, is now just the control

At this point ios/android are nearly as standardized and ubiquitous as TVs were when home consoles started to boom. The 'console', then, is now just the controller. What is stopping companies from launching a controller for mobile exactly as if it were a new console (think launch titles and early game announcements from 1st and 3rd parties)?