Can't say I've ever heard anything about the extinction of PUP's myself. As some have pointed out already, there are always lots of sold signs on them every time I take in an RV show and sale. Their ease of towing and the fact that they are so close to the tenting experience, but better, is what keeps people buying. I just can't see the manufacturers bailing on selling them.
2012 Chevy Silverado 2500HD Z-71
, Crew Cab w/3.73's
2011 Jayco Jayflight Swift 26BH
33 Nights Camping so far in 2016