I'd imagine perhaps their R&D team didn't think of it at the time, or if they did, they wanted to save it for another point upgrade. Software and hardware companies seem to do that sort of thing all the time. I'm sure, for instance, Intel can develop a 10GHz (or faster) processor right now, but they won't distribute it to the public yet, because they'll make more money selling you everything leading up to that speed little by little. ;-)

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Tools :  3dsmax 2015, Daz Studio 4.6, PoserPro 2012, Blender v2.74

System: Pentium QuadCore i7, under Win 8, GeForce GTX 780 / 2GB GPU.