Here's an easy question for you: why is a 1982 Buick GNX a sought-after, beloved classic, and a 1982 Buick LeSabre a jalopy that people pick up for $220 on Craigslist? It's because the GNX was a great piece of design with the quality to back it up and the LeSabre wasn't.
The same goes when you're shopping for vintage clothes. Old in and of itself doesn't make something cool, it needs to have been tastefully designed in the first place. It's difference between that teal polyester trench coat from the '80s and your grandad's balling chesterfield from the '40s.