Maybe it's just me, but wearing jeans to a wedding or funeral and not wearing a jacket and tie to a interview immediately signal disrespect and that the guest/candidate is too lazy to put in the requisite effort.
It might. But out here in the Southwest, we don't dress like Saudis even though their garb is better suited to the climate. For a lot less than $4000 New Englanders could wear mountaineering suits and that would probably retain heat and repel the elements better than a suit, but I doubt that one's coming around either.
Ultimately it's just a cultural difference, and searching for rationality behind it isn't going to bear fruit.
