RVIA’s 2014 projection for each of the major RV product types, which included: travel trailers, 206,100 units; fifth-wheels, 73,000 units; folding camping trailers, 11,000 units; truck campers, 3,500 units; combined towable, 293,600 units; Class A motorhomes, 21,000 units; Class B motorhomes, 2,600 units; Class C motorhomes, 18,300; all motorized, 41,900 units; all RVs, 335,500
This is a quote out of RV business. 11,000 units is only 3% of the total RV sales. Obviously consumers aren't to interested in pop-ups.
I have noticed that there isn't as many pop-ups also. I think part of the problem is that there isn't as many manufactures making them anymore. Manufactures probably make more money off of the other type of RVs.