The bar is ostensibly higher for the inexperienced to get involved with programming. But $99 for a developer license is nothing compared to the cost of an Apple ][e, Amiga, Atari, etc. Most kids already have a Mac anyhow. And if they don't, a Mac mini + LCD is not prohibitively expensive. PcC developers have to start on something, too.
I see the iPad as an easier way for a 13 year old to show off his work. And at that age, since you're not living off the money you make, you are largely living off props. And what better way to boost confidence than to have real live customers.
One of us, either you or I, is completely out of touch with the economic state of an average teenager.
while you state that "most kids already have a mac", which i'd disagree with, the costs to acquire that and the iphone/ipod touch that they're actually using to run the app, are much higher than an old computer running linux, where they can make whatever they want for free and distribute it on the internet or at school without having to have anyone else approve it or anonymously judge its quality.
I think most of the commentaries have overlooked the fact that the people who fondly remember typing in programs from the back pages of magazines are themselves extreme outliers, and only become more so with the passage of time. Many more programmers today get their start playing around with web technologies, for example, or through simply deciding to take some classes in college and learn how to do stuff.