> Touch and direct input like a stylus works much better on displays that can sit horizontal (or mostly so). No matter how good a touch interface is, people just physically can't use them for long periods on a vertical display.

Yes, and if you set up a horizontal display for a desk, you're going to end up with neck strain. You could maybe do something at an angle, like a drafting table, but probably still balancing neck and arm issues. And you'd probably need to adjust display construction to reduce the distortion from viewing it at such a high vertical angle.