I understand that way of selling products.
We've also seen that with some 3D engines, where companie or authors goal was just money without real care about users and community.

For DAZ3D , their main goal is selling characters and stuff, i think they have lot lot of market from family, adults interested in easy 3D character making etc ... etc ...
I think they know how big their sales are for this product and know how little the others products are in terms of benefits.

So indeed they won't spend money in maintaining other tools and just concentrate in the essential ones.
That's pure enterprise strategy like any enterprise where you invest money on the good products, and abandon the products that couldn't do enought income : why spending some more money for supporting them ?

I've seen that also with a Database langage system made by a big company and by big Banks, they said they will abandon it end 2010 , and they done it, caus it was somewhat outdated even if used, and they prefer to support some more modern solution they have done.

So i find that selling strategy very natural like any big company, even if they won't make happy some very little part of their users using the other products !