When Apple asserts that a desktop computer should be replaced by a locked-down handheld device with very limited capabilities, the odd thing seems to me is they don't realize these devices do very different things and fulfill very different needs.
I don't worry about the demise of the desktop because I'm nostalgic, I worry about the loss of power and productivity incurred by users with desktop-illiteracy. There are many applications for which a handheld device, especially one with the limitations of iOS, is just not suitable - in much the same way a full desktop/laptop computer is not suitable for things mobile devices excel at.
That the hardware is locked down, outdated, and supremely expensive are additional criteria making the disconnect worse, but these are not the crux of the problem in my opinion. I see two outcomes from this, neither one is appealing: either Apple is misjudging the needs of their users, to the point where trendsetters like programmers will be switching away from the platform. Or, they succeed in their vision and breed several generations of technologically illiterate information workers fumbling their way through life with nothing but extremely limited mobile devices as their only productivity tool.