The problem with touch screens for desktop use in the corporate world are many.
1. You end up with a lot of fingerprints on your screen.
2. It's awkward, inconvenient, and not very ergonomic to have to touch the screen to do everything. Much faster to have a hand on the mouse to get around the screen.
3. A touch screen isn't as precise as a mouse for detail work unless you are using a stylus.
4. To overcome 2, the screen would need to be the keyboard. Hard to share your screen with a coworker at that point.
Touch screens are useful in some instances and could be a nice option but they will never completely replace some version of the keyboard and mouse for a desktop just as voice command driven interfaces will never be the only computer input device for offices.