And then there is the issue of open cell foam and closed cell foam, and the difference between the "old foam rubber" that had resilience(bounced back) and the cheap foam that collapses under load and stays collapsed. I agree with Rob's first comment. there are many types of foam rubber.
In a CMP, a person with the genetics of a Dutchman may not need thick rubber. He might much prefer a thinner cushion of superior quality.
