The _vast_ majority of iPhone apps are basically analogous to web pages, not Debian applications.
Remember when the web "took off". Every double-glazing sales company, rat catcher and accountant wanted a web site right away. They'd all call up some spotty kid who happened to know a bit of HTML and he'd make them their very own web site for a reasonable price. And then they'd go pay the sign painter to write "Threepalmvalleycentralheating.obscureisp.com" on the side of their vans.
The spotty kid would eventually figure out that he's paying himself minimum wage because he's lousy at business finance and he's no longer excited about making web pages, and the rat catcher would figure out that the web isn't bringing in much business. But meanwhile business was "booming".
That's where the iPhone is now. Countless people have breathlessly told me that they're now an iPhone developer, and hey that means they can buy a new iThing every couple of months and see it as a business expense, and oh, the money? Well they don't have the money part figured out yet. In 18 months most of them will be back working for the Man. But meanwhile they're generating thousands of me too apps, and more importantly, tens of thousands of very niche special purpose apps for just a handful of people, which outside the Reality Distortion Field would have just been web pages (especially since they often don't work without Internet access)
Imagine if there were debian packages like view-lwn-kinda-like-a-web-browser.deb and view-phoronix-sorta-like-a-web-browser.deb would you be more impressed and believe Debian was going to explode in popularity? Or would you think its developers had gone crazy? For Debian thousands of worthless packages is a cost, so they're against it. For Apple every "Hello, world" app is money in the bank.