Step 1: make some affordable accessories to comfortably set up a tablet as if it were a PC monitor; keyboard, speakers, etc.
Step 2: start marketing parts instead of finished products only so it isn't an entire industry of iMacs. Let people build their own.
Step 3: open things up and give people more control over what they do with their devices; if you buy it you get to decide how it's used.
Boom, tablets are the new PCs. Not a replacement, simply an evolution out of the old form. Until all this happens they'll still just be a gimmicky toy that some people happen to spend a lot of time on. Make these things happen and you'll see business tablets as well.