Wouldn’t that eventually be just a modem/router, monitor, and keyboard.
The concept of window isn’t going to go away anytime soon. And a brisk graphical bandwidth is going to matter.
The replacement for the PC will be the PC.
It might be Linux, running Windowy things via the AmazonNet (as an example).
Modem/routers would have to possess some of the abilities of small PCs or at least a “streambox” like Apple TV or Roku. Anything capable of running a web browser should be able to reach web-based storage and apps.