Sebasistan
100+ Head-Fier
The sales man or woman.
Once the sales man has sussed out their customer they use the word which the customer wants to hear.....outcome sale!
Have you noticed how all the IEM manufacturers say in their blurb on phones with Est, the particular set "has been in development for...", take your pick, 2,3,4 years. The fact is the drivers may have been in development for however many years but the particular set was dreamt up recently because those drivers now exist.
My point is those selling to us will dream up the angle on which they can sell their "vintage" product. Such as "in its day no other product could match it, today you have to pay a fortune for quality like this vintage masterpiece". Solid 1920s bakelite....in reality plastic in its infancy.
Edit: prematurely posted - please reserve your comments on that.
Have you noticed painting are old but not vintage. Whereas cars are vintage but not old.
I mean, in that regard I would say, vintage is old, but still usable without too many issues.
Old is... IDK, something that's old but simply not usable unless you're investing a lot of energy.
In terms of cars, IDK, a fancy / cool car from the 70s is vintage, whereas a Ford Model T would be OLD?
Where would that fall in audio gear, maybe an old ass pair of headphones from the 40s that you'd need to completely rewire to use at all would be OLD. A pair of headphones from the 70s that's already using a standardized plug that's still in use today would be vintage? (Unless it's like an off brand cheap thing that for some reason still works. I guess in that case it's a question of the sales person and the overall condition.)
At the end of the day it's very malleable and I guess you're right it's ultimately a sales pitch.