It would be rather simple to have a soft-root that allows root-like implementation without affecting the actual core files of the system. The iPod deploys with a ROM section for the core files to restore the system, truly this is all the iPhone or iPad need (and AFAIK both have). You would only require a more foolproof implementation to ensure even the gravest idiot would be able to save their device by plugging it into their PC.

However, I believe your latter point is right. I won't dump any amount of money on an iPhone/iPad until it's able to run multiple programs, and until it is route access is likely pointless.