CNBC’s breathless coverage of the iPhone debut reminds me of the fawning treatment they gave Krispy Kreme a few years back when the ill-fated donut vendor went public. I can recall Joe Kernen in particular effusing over the company’s supposedly limitless prospects as though KK were selling a cheap cure for cancer. More like a cure for fitness. In retrospect, we wonder how Kernen and just about every other analyst failed to foresee that a donut chain’s success would not long endure in this diet-obsessed land of ours. Americans were going to have their brief fling with Krispy Kreme, queuing around the block for a taste of sin, then go back to calorie-counting as usual. Which they did, as you might infer from the chart below. But do let me know if the company comes up with a 100-calorie donut that tastes like the real thing, since that’s when we will all want to buy as much KKD stock as we can get our hands on.

Donuts were big for a brief while, but the huge amount of publicity being lavished on iPhone makes Krispy Kreme mania look pretty subdued in comparison. The launch of the device is being treated like the Second Coming by the news media, even if most reviewers have not failed to notice that iPhone ownership will come at a steep price. Six-hundred clams plus tax is a lot to pay for a gizmo that can’t retrieve office e-mail and which will facilitate phone calls only in those areas of the country served by AT&T’s somewhat spotty network. Throw in a no-discount, two-year phone plan and, well, early adopters are still going to be queuing around the block to get their hands on one. But will millions of well-satisfied Blackberry users make the switch? Probably not, at least not initially, since they are mainly business users who are not apt to be easily enticed by a device merely because it looks like “fun.”

Which it does. We’ve seen the iPhone featured in so many news spots in the last few days that we could probably operate one without using the instruction manual. It looks cool, all right, and it apparently does many things well. Even so, we remain skeptical that it is destined to become the category killer that iPod is. We shall see.