The silicon only has to be fancy, because phones are so constraint in terms of space, power and cooling.
Getting phone-like performance in a desktop or laptop form factor and power and cooling budget is a lot simpler and cheaper.
> They don't have to buy a new device but can still get a mouse/keyboard/display combo and so some "productivity tasks".
The point was that they do have to buy a new device. The only thing they don't have to buy is new silicon. But that's trivial compared to everything else.