"The same argument applies to DS4. Or do you think it's just Poser users who are slow to upgrade to the newest/greatest piece of software?"

True, however, you can get behind the weight map curtain for free with DS. One can argue about how useable the free version is, but anyone who has the system to run it can get a good idea whether the technology is something they want to invest in. I don't even see a demo of P9 on the SM Poser page. In either case, some users (perhaps quite a few) are not going to upgrade either product unless they see a pretty big reason to do so. If you want to use the OS metaphor, look at how long XP has lasted, even discounting the Vista debacle.

Genesis may be cool but not necessarily enough for many to abandon the traditional discreet figure model. Weight mapping may be even less compelling. Consumers don't likely care how much easier it is to rig for. They only care about the end result. Yes the figures may bend better, but outside the cognescenti, amongst those using mainly stock poses and perhaps having a less critical eye, I'm not sure how much of a selling point that is. It seems to me that the people most likely to upgrade primarily for weight mapping are those who were dissatisfied enough with V4's flexibility to have already gravitated to Antonia (standard), Apollo etc. for their reputed superiority in that regard - or who have tried all of the V4 joint fixes and found them wanting. Personally, I would see soft body dynamics as a much bigger must have. 

"Democracy is a pathetic belief in the collective wisdom of individual ignorance." - H. L. Mencken