Agreed, especially today. Back in the 1980s (when clothiers switched from pattern sizes to catalog sizes), a size 12 woman  , especially if she's tall, MIGHT not be   625  fat. But since today's size 6 (which was the smallest readily available size till late in the 1980s)  would be marked at least size 12  in 1983, if you could teleport  a 2019 size 12 garment back to 1983 ,  I would guess it would be a size 18 or 20 . And in the 1950s, when pattern sizing was still used-? There  may not have been  any clothes outside specialty shops that would be so huge.