Big, wrong ideas are destructive, and the two biggest, wrongest ones right now seem to be: "desktops are just out-of-date tablets", and "the only good affordance is a dead affordance".
Affordances are what make computers humane, and there's a world of difference between how phones are used (mostly social), tablets are used (mostly media consumption), and how desktops are used (mostly productivity).
The visionaries in charge of all three of Windows/OSX/Linux are of similar mind about the "big ideas", and it's caused a lot of grief for productive people.