It'll be "we've sold 10,000,000 units".
They're not selling a tabet PC - they're selling a user interface. One should never mistake what Apple is actually selling. The iPhone is beaten by dozens of phones in terms of flexibility and power - but still outsells them because of its interface.
Quite simply, in answer to you question - I AM the "tech-unsavvy Mr. Consumer" and my reply to you is: "It's purty. I want it."
It's easy to adopt the cynical tech-savvy POV. Everyone did with the iPod and the iPhone. And they were wrong - they sold 75 million of the things. I don't think there's any mileage in trying to outguess Apple's marketing experts and predict dire failure; it'll sell, and we all know it will.
Apple has certainly had marketing failures in the past. How's your Apple TV and Mac Mini working out for you? Yeah, me neither. If you're just laying out that much money for things that are just "purty" without much regard for its actual feature set, then you are not "Mr. Consumer". A consumer pays that kind of money for an HDTV, but they know what they get for it and what they're going to do with it. They didn't pay what the industry wanted for Blu-Ray players OTOH; they had to come down quite a bit before consumer demand tilted in their favor. Portraying the average consumer as carefree with their money is a bad characterization.
The iPad won't bellyflop the way Apple TV did, but I don't think it will "own the market" or "lay waste to the competition". That's a little over-the-top. Mega-success is not a fait accompli. Any assertion that it is seems to be based on little other than a hype machine and a (falsely) perception that consumers are commited to buying shiny baubles. Personally, I was actually harboring very high hopes tinged with a dread of a $1000 kiss of death pricetag. It's priced to appeal in at least some markets, but it's no replacement for a netbook, nor is it the all-purpose device I (among others) was fantasizing about. Basically, if Mr. Consumer was in the market for a device along the lines of an iPod Touch or Kindle, he'd now have another product to consider, rather than a hands-down no-brainer.
I want to touch upon the "everyone was cynical about the iPod and iPhone" remark, because it raises an eyebrow. The iPod and iPhone did not succeed in spite of the "tech crowd", they succeeded because of'em. Techies love Apple The iPod and iPhone were highly-rated-and-reviewed award-winning devices thanks to an innovative knockout combo of both the UI and hardware. The app store was a real watershed.
I still hope to find that killer feature that I overlooked or got bad intel on. I am a fan of Apple, and the simple truth is I don't see in what way, shape, or form this supplements anything I do to the extent that I need it to, which is in large part due to the iPhone I use constantly. I even have lousy eyesight, which would make the big screen more useful for play GTA:CW...but I need something more.
Currently, my research is to see if I can tether my iPhone to one. And I gotta hope Steel is right about the Safari browser getting some much-needed refinement; for one thing, I would really love to read Marvel's digital comics on it (maybe Marvel will put out an app).