It may also be that the younger crowd, in this case I am talking about people who are under 65-70 are generally not interested in a large class A motorhome, instead they are more interested in an RV which can be used to get back to nature, fit in smaller campgrounds, or go places a diesel pusher just should not go.
I am part of this younger group, being just barely in my 50's, and I own a small 28 ft now 18 year old class A motorhome (currently mid way through a 3,200 mile month long loop of the southwestern US). When I speak with friends, family, and just people I know who also own RV's I find the above to be true. They either own a 5th wheel which they "take to the lake" seasonally, where it sits for much of the year, accumulating only a couple of hundred road miles per year, but many weekends of use per year. Or they have usually a small travel trailer, that they use for "camping", which often may mean dry camping, traveling to state parks, etc. mostly within a day or two driving distance from home.