While there is truth to this even the poorer classes didn’t dress exclusively in ratty brown sacks or whatever fiction keeps trying to push on people as “historical” dress for lower classes. Workers didn’t dress as nicely, no, but that doesn’t mean they didn’t care about their appearance and didn’t try to follow fashion trends and didn’t have access to dyes. They wouldn’t have worn their nicest clothes while sowing fields of course but they always got their nicer tunics out for Sunday Mass, festivals, weddings, and so on.