I've read most of this thread and contributed my own opinions as well, but I am having trouble finding where anyone suggested that vintage bicycles have "performance advantages" over modern bikes. Several contributors have very openly stated that they understand the opposite is true but enjoy riding vintage bicycles regardless. If "comfort" is being classified as a measure of performance, I think that is less about the frame material than about the fact that typical tire widths and pressures, the inherent flexibility of older frames and components, and more pleasant leather or cushioned saddles are associated with the comfort of vintage bicycles versus modern ones. I'm sure if I put a Brooks on my Look 675 and deflated the tires down to 75psi like I ride on most of my old 27" rims, that bike would feel pretty darn comfortable too... But I also didn't really see anyone in this thread suggesting that comfort was a performance indicator that makes old bikes any better than new ones.

Essentially, the only "clarity" your last post has provided is the fact that you are making up arguments to reply to because you want to express your irrelevant opinions for some reason.

-Gregory