Yes, many commercial (and freebie) add-ons have been offered this way.  For example, I recall the Mog Ruith elven house;  an alternative Celtic great hall version was released several months later, as a set of props just like the original.  But these prop files referenced the Mog Ruith geometries, so you had to have the original Mog Ruith product to use the Celtic pack.  I recall a gazebo for which I have three add-on versions.  For things like the DAZ Morphing Fantasy Dress, the list of commercial and freebie add-ons is quite long.  All the add-on cr2s reference the original DAZ OBJ.

     This is very common practice, and allowing for this is a major reason that many places require remotely referenced geometries.  In this method, even if they cannot model or UV map, texture artists can contribute new alternatives complementing the original product.  All those umpteen items in the stores with names like Leannan Sidhe for the Mog Ruith Gazebo, or Party Time for the MFD are using this sytem.

     The original Morphing Fantasy Dress had only a simple texture.  But DAZ had done the hard part (modeling, mapping, creating morphs, even providing templates), and then a texture artist could scan cloth swatches and paint a new texture, apply it, and re-save the dress as a new cr2.  Their new cr2 referenced the DAZ OBJ, so it respects copyright. Such an add-on can be sold commercially or offered as a freebie.

     Another reason  for stripping out the geometry is to facilitate use of the item in some other rendering studio.  Most any 3D program can swallow an OBJ, but they may not be able to interpret a Poser pp2 or cr2.

Poser 12, in feet.  

OSes:  Win7Prox64, Win7Ultx64

Silo Pro 2.5.6 64bit, Vue Infinite 2014.7, Genetica 4.0 Studio, UV Mapper Pro, UV Layout Pro, PhotoImpact X3, GIF Animator 5