I think this is a strawman logical fallacy. Or you are not seeing the forest through the trees. It looks like you are setting up casing tension as the ultimate measure. But it is truly irrelevant. Those experts are finding the fastest system, and they do not care about casing tension. They are using their testing protocols to determine the fastest combination of wheel, tire, tire width, and tire pressure for their riders. The end result is that many of them are on wider tires, some as wide as 28mm. And they are on lower pressure too, but not as low as the 5 bar hookless max.
I'm not sure I need anyone to quantify comfort. Though, marcag did make an effort to capture that from his riders.

My personal experience is that I did a fondo event on a demo bike. I had no agenda and no plan to buy a new bike - I loved my 7 year old bike. I did a test ride on chipseal pavement and was blown away by how much smoother it was. My friend at the event had the exact same reaction on his demo bike. It was kinda unbelievable how much better the wider tubeless felt. Both of us were running 25mm on our personal bikes, but at 80 PSI. We talked to several of the pros in the event about bike comfort, wide tires, pressure, etc. By the end of the event, I decided to buy one of those bikes, almost on the spot. It is radically more comfortable than my former bike.

It is my road bike, and I do not ride it for maximum speed, so that was not part of my decision. But the consensus opinion from reading here, by other experts, and a few former pros, is that you do not give up much speed, if any, on wide tires at 60-ish PSI. And the comfort factor is a huge bonus.