IMO the main purpose of web design has always been to signal that the site is a "legitimate" entity, ie. run by people with sufficient clout to pay professional

IMO the main purpose of web design has always been to signal that the site is a "legitimate" entity, ie. run by people with sufficient clout to pay professional designers to keep up to date with the latest fashions. Users like those signals, and will say things like "lol, 2011 called and it wants your site back" if you don't play the game.