Any question answered...

Any thoughts on that?

Perceived ride and handling differences between 31.8 and 26.0 are placebo effects. The effects fall below the threshold of human perception if you have the right tyre pressure, mostly because fat bars exploit geometry to obtain similar stiffness to thin ones while being lighter, rather than using the same amount of material to make a substantially stiffer product. There is a small aero gain from using thin bars if they are tubes of circular cross section, but it's irrelevant because nobody chasing the aeros would use round metal tubes anyway.