Yep, amazing how poor the mattress is in new trailers. I think they are the new 'springless' versions
My guess is that manufacturers have a hard time getting more money for a better mattress when shoppers can't 'see' the difference. It's like trying to sell people on 'better' thicker insulation or other items that can't be readily seen or appreciated.
We had the same problem on our 2007 TT. Bought a memory foam topper and that made a huge difference. Just did the same thing before our first trip in our new ST. Topper arrived today from Amazon.