You are likely not getting responses because your link is not clickable, and if I copy and paste it into the browser, I get routed to a site that requires registration.
Assuming that the 2019 5th wheel is priced lower than the 2020, I would attribute it to excess inventory of the 2019 stock. I've read that motor homes and 5th wheels are overstocked everywhere because sales have dropped off significantly. That said, you should probably be able to get an excellent deal on a 2019.
2004 Tiffin Allegro 27.5 ft. P32 18,000 lb GVW. 8.1 liter. Workhorse chassis built May 2002. 24,500 miles. 2012 Jeep Liberty Toad. RVi2 brake unit.