They are barriers because if Apple added an "advanced" button somewhere that gives you root, then tons of ordinary users would press it (perhaps after being ins

They are barriers because if Apple added an "advanced" button somewhere that gives you root, then tons of ordinary users would press it (perhaps after being instructed to by an online tutorial, or by a scam), break things, and find that their iPod does not "just work" and be unhappy. Apple would be adding a button that you can press to enable your device to get malware, and that will confuse and harm lots of people. It's not obvious how to add an advanced button that the right people will press, and others won't. You can hide it, but it will get reported on websites that newbies see, with simple instructions. But that said, I'm sure there's a solution, and I hope Apple finds it. I think the development effort from Apple to enable stuff which would only be used by a fraction of the audience -- even done to Apple's high standards of polish -- is a secondary and more minor issue. Apple can afford it, and Apple knows that developers are worth the expense. However, in terms of development time rather than money (which aren't equivalent because finding, hiring, and training good programmers is hard), this has to be lower priority than enabling multiple programs to run at once and some other stuff, so maybe it'll be a while.