As much as you all like to hang on every sartorial breath that emanates out of the mouth of Barbera, he is an old man, with an old man physique.
He may look good in his tailored clothing, but tailored clothing is designed to do that that, make people with less than ideal body shape look good.
He avoids jeans because he would not look good in them.
Interesting. However, I never saw a single jeans that had a good silhouette, i.e., it does no good to any physique, but my statement is biased towards the conservatives.