I bought a piece of 1.5 inch stiff foam to try to fix a sag in a bed. It didn’t work but having that thick piece of solid foam around has been a life saver.
Need something flat to put a laptop on? Throw it on the foam. Going to be doing something that requires you to be on your knees for a while? Get the foam!
It went from stupid purchase to something I’d gladly replace if it broke.
I’m guessing it’s just priced as a luxury item, not related to actual cost. Wealthy people will shell that out without blinking. Then when they sell enough at that price, they’ll start dropping it to get other buyers.