You know, if you think about it, you're putting, at times, all your weight on the saddle. That's 150-200lbs. And that force is being exerted on a very small surface area..2 areas the size or your thumbprint pretty much. What is that foam doing exactly under those kinds of load??? It's have to be some seriously firm closed cell foam to do anything at all. So I think most of that foam is for lighter loads..but the serious support is being done by the shell itself..so a good saddle with appropriate flex in the right areas I think is more important. If you can push the foam in more than 1/2" with your thumb, it's not doing anything at all I think.
One of the most comfortable saddles I've ever had was the Selle Italia Flite Evolution (and later the Evo3) which had no padding whatsoever. Just a somewhat flexible carbon shell.