How long is 'since forever'?

First, when I started cycling, I wore wool shorts with a chamois liner. In this case 'chamois' refers to leather from a chamois. It was incredibly smooth when wet, from sweat, for example, and I believe that smoothness prevented chafing. It was not padding. At least one other poster mentioned chamois, but he made his point more subtly.

Second, if you look for images on the web of vintage bicycle seats, you'll see some padded ones. I rode an Avocet Touring I for decades, and it was padded, though it's a fairly recent development as I count time.

Is it really necessary to mention that invalid assumptions generally lead to messed up thinking?

Third, you raised an experimental question. What have your results been? Did you search for published reports of experiments? Did you do any experiments yourself? I suggest you try out padding on your seat for your next few races or, even, training rides. You might find something that makes you a billion bucks ... although padded seats have never driven unpadded ones out of the market, which should tell you something.