You won't be sitting there hunched over a tablet. But you might hook your tablet to a monitor, attach a keyboard and mouse to it, and run "conventional" software.
Monitors, keyboards, and mice aren't going anywhere. But it won't be very many years before a desktop machine becomes a niche item for those who even today can't get enough power (3D artists, etc), while the rest of use are using one variety or another of portable core device with multiple IO options. (Though it isn't tomorrow, either. This stuff actually exists now, but it's bleeding, bleeding edge, as in the "cut yourself" type of bleeding edge. But still, that will fix itself.)
Monitors, keyboards, and mice aren't going anywhere. But it won't be very many years before a desktop machine becomes a niche item for those who even today can't get enough power (3D artists, etc), while the rest of use are using one variety or another of portable core device with multiple IO options. (Though it isn't tomorrow, either. This stuff actually exists now, but it's bleeding, bleeding edge, as in the "cut yourself" type of bleeding edge. But still, that will fix itself.)