(How about 3/4 pants among the patagucci crowd?)
Fashion evolves toward ever greater complexity as a Veblen status-signalling good, then recapitulates. Often it is lower-class wear which emerges as the new standard, then progresses through the cycle again, often being elevated to the status of elite wear: dinner jackets, morning coats, longe suit, three-piece suit, dungarees, designer jeans, button-downs and khakis, etc.
Several of those transitions followed major shocks: WWI, Great Depression, WWII, the Civil Rights and anti-Vietnam movements especially. The 2001, 2007, and 2020 economic panics similarly, though the last most notably IMO.
(Arguably Fast Fashion was a business response to the 2007-9 crisis.)
The fast-fashion trend seemed heading for a fall. Covid-19 delivered the kick.
Rule of thumb: the waitstaff in restaurants wear what the patrons had been dining in, before the last fashion shift. In the Coming Age of Formal Sweatpants, I'm guessing the front of the house will adopt button-downs and khakis.
(Browsing old pictures makes it clear the Iron Curtain was pervious to even minor changes in fashion. There may have been ideological opposition among the elites on both sides, but not only did We look, from the oh-so-distant viewpoint of the twenty-first century, silly in our wide lapels or legwarmers, They did too.)