James and Jessie probably had more content designed for them than any of the native Poser people ever did.  When the G2 versions of them were released there were a lot of clothing sets and accessories for them (still available on Content Paradise in fact).  I actually thought that Don and Judy were decent looking and yet no one did anything for them.   Actually I think Jesse and James did enjoy some fleeting popularity when they first came out; people touted them as being more real world looking than their Daz contemporaries at the time.  At least the Poser native figures always had and I hope always will have genitalia.  They are now being offered only as a Pro option for V5 and M5 for the Genesis figure--a human figure isn't complete without genitals--for the longest time Victoria had nothing below the belt--at least she has an "option" now.

I think when discussed on other threads and in other forums, the biggest reason people don't use the Poser native people is that they are just UGLY!  The male figures don't have pleasing body shapes or faces.  If content providers did create stuff for Allyson and Ryan, for instance no one would buy it.  Why buy stuff for them when M4 and V4 are gourgeous out of the box. Take a look at this banner I made for the Poser Gallery--there is devolution from P5 on.  People were able to make more attractive add ons for Dork and Posette.