Yeah, that's what I was getting at. Wet layers under a drysuit don't work, and if you sweat like I do (think of a fat kid jumping rope in the attic) those wicking and insulating layers become saturated pretty quickly and lose their effectiveness. Now I'm wet on the inside as well as the outside- heat starts to transfer. It's better than not wearing anything, but it's not going to give me the advertised protection.
Not that I worry about this stuff anymore. Instead I focus on making sure that my super insulated coffee mug indeed keeps my coffee hot for a minimum of 6 hours- because cold, crappy coffee is a no-go criteria where I'm at now.