Desktops are just hardware.

Sure. But more important than what they look like or whether or not they're sideways are the other properties of that hardware:

• Upgradeable and repairable with widely available replacement parts

• General purpose and capable of running any software you put on them

What I'm worried about is the desktop being replaced by something that meets neither of those points, resulting in a far worse experience for any person who wants to customize, maintain, and fully control their own computer, especially if they'd like to do so without interference from a huge corporation.