Well, maybe completely disassembled might not be that practical, but it would perhaps depend of the figure. One of the first HTs I got was Deunan Knute, which came with her head, hands and feet off. If that's all it took to knock 10% off the MSRP, I'd be all for it. And maybe if the figure was easy to dress, you can get a bit more taken off the base price, like say 20-25%. After all, the Joker DX (and maybe some other figures that I can't remember offhand) had the extra outfit that you had to go and buy a separate figure for. That didn't seem too difficult.
Of course it wouldn't be practical for all figures. Like you said, Cap looked fairly complicated to fully dress. But things like the head, hands and feet would be do-able for Cap. Maybe part of the DX "package" is that it comes fully assembled, which adds to that luxury brand.
Just something to think about with regards to the rising prices!