Supposedly the software industry is very concerned about user interface and usability. I'd say that concern isn't keeping many of the big players awake at night. Especially Apple. While there isn't exactly an industry for portability, there should be. Nobody gets it. Bill Hewlett got it, in 1971/1972 when he personally insisted on a portable pocketable scientific calculator, which evolved into the first personal (pocketable) computer in early 1974. Bill was rare, and I was right there at the cash register when the first unit came out. The lack of decent fully portable iPod DAC's is completely in line with the (still!) complete avoidance of the docking issue by Apple et al - i.e. why would anyone want to "dock" their handheld computer into a system that doesn't have access to all of the facilities of that computer? You think this might be off the mark? In the early 1980's HP produced a series of small pocket sized computers with one-line displays, but with the capability to "dock" with up to 900 peripherals simultaneously on a serial bus, much like USB. And so external keyboards and full-size monitors became available for that bus, and you could do work on that fully-functional desktop system, then, pull the serial plug from the pocket sized CPU and put in in pocket and walk away with everything in your pocket. Except keyboard, screen, external disk drives etc. But today we have primitive docks with only a couple of marginal vendors supplying dock extension cables, quality unknown. How can that be, with hundreds of millions of these little computers sold?
Oh, wait - I think I have the answer. HP encouraged third party peripheral support with free documentation of the interfaces, and Apple is the opposite of that. (Note: that was the old HP, not the current HP)