as stated, just because they are old means nothing...if people wear them it is promoting them as a fashion item...and therefore keeps the trade alive
the only use i can see that is somewhat legitimate is perhaps period clothing for film, tv, documentaries etc to assist with realism etc...but even then not strictly necessary...
i have acquired some revolting fur stoles - full animal body - and a woman from a nearby shop that sells vintage stuff said shed pay about £10 for them....personallty id rather burn them...but...if everyone did that, people would end up buying new ones...vicious circle really
but try period costumiers