Just like almost everything else, some writers like to go against the grain, in hopes that at least one their contrarian views is correct and they can claim to be, from that point on, a "guru".
Most of ZDnet's writers have been much more favorable to webOS and, are really looking forward to its release.. this one dude is a blogger with a goal to become one of their writers, so, he's willing to go out on a limb and make all sorts of projections that others may find a bit of a stretch.
While he does make some valid points, the brazen and arrogant title of his article is a huge clue to his real intentions, as I alluded to above...
HP's Apotheker said that this isnt a sprint, its a marathon... whatever the TP does out of the gate won't matter as much as what happens after it is released and more WebOS products, pads/smartphones are released and increase the WebOS brand and draw more users into the ecosystem, over time.
That's how you build a brand and gain real solid market share.. something HP knows an awful lot about.