But the ZX-100 is in the audiophile segment, a segment that doesn't struggle with prices as much as other segments. Every incremental upgrade is a minor reason to buy a new device amongst many of this segment. There even are people in the ZX100 thread who claim that they hardly hear the difference between an A15 and a ZX100, yet the ZX100 sells to those it caters to. And these people are willing to spend that little more to have a more professional looking device and other features that just 'marginally' improve SQ (not so weird, given that there are audiophiles who pay up to 1000$ for just a better power cable lol) ; I think Sony would be foolish not to exploit the price gap between the A30 and the WM-A1. The A30 might sound good, but it doesn't share bigger amps, protected copper jacks and premium build quality of the more expensive devices.
Anyhow, at the end of the day (end of january actually) I'd have no major qualms over buying a NW-A30 but I would happily spend 200-400$ more for a higher model if it fulfills the above features. By no standards can I be classified as rich, however things like this (audio 'coziness) is where I get comfort from, thus I spend.