Of course you can pull the DP connections out, that's not the problem. The problem is that when you put that display on a windows machine, you end up with a bunch of legacy windows software and web graphics content that looks unreadably small, followed unhappy users who return those fancy DP panels to your retailers.
Of course, the same thing is true of iOS and OS X software, which is precisely the reason "Retina" (as distinguished from arbitrary 200+ DPI hardware) displays are always shipped in resolutions that exactly double those of pre-existing devices. So even though the legacy software doesn't handle it Apple, by controlling the framework, is able to make it work more or less seamlessly.
Dell and HP don't have that freedom, they need help from Microsoft, and Microsoft, well... At least Windows 8 does high DPI natively, though the MS decision was basically to jettison legacy visuals and hope no one runs the old software anymore.