The weight reduction game really kicked into high gear in the mid to late 90s. Rv OEMs lightened things up, used thinner materials, rubber roofs and RVs became disposable items like many other things from that era to the present day, again in the name of fuel economy and enabling lesser tow rigs to pull long trailers
With these new rigs, when they need a new roof, the rig has depreciated so much by that point that the roof costs more than the trailer is worth so they get scrapped. New rigs are nice though, but so many get suckered into spending 30k plus on a new camper, then realize they don't have time to go so they sit and depreciate. Some who can't park them at their house pay $50 plus per month to keep them at a storage lot on top of that. Just crazy.
I see many Campers at a storage lot close to my house that havent moved for 2 plus years. Some As and 5th wheels that have to be 50k plus rigs. One at a neighbors house they bought 3 yrs ago I've never seen move once. I don't get it, but to each their own