And thus speculation thrives...
1) a comic shop selling the book the day it's out for more than cover price isn't actually a case of comic book "speculation". It's more like what you would call price-gouging. For a legitimate comic book shop with regular customers, kind of a dick move. But then, DC it the one who set them up for it.
2) it's mainly collectors and/or people who couldn't get the covers they wanted, again thanks to DC, who are paying over-cover price for them. There really isn't any secret cabal of speculators who imagine 3D covers will be a good long-term investment, most especially not if they're already paying 10-50 bucks for them. All you have to do to realize that is look at the price of most New52DC #1s now as opposed to when they debuted with more demand than supply.
From what I saw, about 30% of comics shops marked them up to some degree, even just a $1, on the day of release. These covers appeal to the collectors.