I agree with the article. Other manufacturers have had a decade to inspire people with tablets, and failed. People don't want a desktop pc in another form factor.
You're right that they've rejected the TabletPC as offered. But we don't really know whether they want a big iPhone either. Time will tell if this is an iPod or an AppleTV, iPhone or Airport.
As said (ZeroGravitas), people want a desktop in another form: laptops, smart-phones, handhelds, gaming devices (PSP, DS), MP3/MP4 players...
Others did not fail. But Apple is very good at creating wannahaves. With the iPad they created another one. People will pay lots of money for this device because it's a hype. And that is what Apple does. Creating hypes.
The iPad is nothing new. But it's got this 'look at me' factor. But try using it in the sun.... The Adam does a better job there.