Maybe cause the iPhone is more than just a cellphone, it falls under a different category. But on one of those shows like Dateline or something, they said that by law, all cellphones are returnable for full credit for 14 days and even the service itself can be terminated and the customer only pays for just the minutes used. Now whether or not retailers actually follow the letter of the law is another thing. I'm sure people don't know their rights or the laws concerning cellphones and just allow retailers to charge them fees.
But as far as price protection goes, most retailers have some sort of price protection guarantee on their products. And being that Apple is both the manufacturer and retailer, it can get kind of confusing, but the Apple Store's price protection policy is no different that any other larger retailer's policy. Again, it's nothing special.
For example, here's Best Buy's price guarantee...
Already bought? We'll refund you the price difference, plus an additional 10% of that difference up to 30 days after your purchase (14 days on select categories*, 60 days on HDTVs purchased from 6/3/07 through 9/29/07).
* Select Categories include desktop computers, notebooks, projectors, monitors, camcorders, digital cameras, radar detectors and video games purchased as used.
So as you can see. Not only is Apple's 14 day only about half of what Best Buy's, Best Buy even gives you an additional 10% for the hassle.