Why do middle-class men feel confident dressing as slobs today?, Steve Sailer asks:
Their grandfathers would have been anxious that merchants would snub them as bad credit risks if they went about their errands dressed like California Gold Rush prospectors. Why aren’t we?
Because we have credit cards.
Americans always dressed less formally than Europeans, but our ancestors worried about looking respectable. Because of the country’s sprawling size, American commercial life was peculiarly vulnerable to traveling con men. Judging a man by how spiffily he dressed still left businesses susceptible to the occasional natty fraud like Professor Harold Hill in The Music Man, but most criminals can’t be bothered with routine aesthetic upkeep.
Today, though, if a guest trashes his hotel room, it just goes on his Visa card. As Hunter S. Thompson discovered to his delight in Las Vegas in 1971, the modern credit system had made his paranoia about impressing desk clerks obsolete.
Commenter Nergol prefers another explanation:
I prefer Oswald Spengler’s explanation, which was that in rising cultures, the poor imitate the mannerisms of the rich, whereas in declining cultures, the rich imitate the manners of the poor. Check out Dan Carlin’s description of Clodius Pulcher in his excellent recent podcast series on the end of the Roman Republic to see where that’s come up in history before.