Obryn
Hero
.... And if we're playing what-if, if WotC had not made the OGL, they would not be in the unenviable position of competing with their own gamesIsn't that sort of like saying "You can't fire me. I quit!"? They stopped producing books for a reason.
The broader point, though, is that if WotC had stuck with the core elements of the game and with the OGL, there wouldn't be a large enough market for other games for any of this to have happened.

Keep in mind - before moving on from 4e, they also moved on from 3.5, 3e, and 2e. All for a reason.