Unfinished seams does not mean just poor or... avantgarde. The rich Roman noble people wore their costumes seams unsewn and even ruffled as clothes did not have to last.
When you hunt, do you hunt because you do not have money to buy meat? This is what happens with vintage clothes as well.
Chanel`s famous tailleur has got its sleeve edges double seamed to resist more, it was the 50s and war and poverty cultural habits remain. (normally a jacket starts to wear at the collar and sleeve edges).
What the hell is happening with unisex clothes everywhere? And all these women dressed as men and men dressed like women? Nothing new here. Think about the old Greeks and how ressemblant the costume was for noble men and women.