Do not think it tis just "chic" driving up prices/sparking interest in vintage appliances.
One factor is the tail end of the baby boom generation and Gen Xers are buying refurnishing homes, and the 1970s and 1980's are "hot" now. For one group it reminds them of their youth (Brady Bunch, Bewitched, and all those kitchens of their mothers, aunts, grandmothers etc in harvest gold, avacodo, and poppy). For the other goup it is retro "revival".
Finally with more and more "major" appliances sold today one step up from highland cattle, or just poor quality and design, they are discovering vintage appliances were built to last. The fact that one can find quite allot of these "vintage" appliances still around, many, many in working order speaks volumes. Today's "made in Asia" garbarge is lucky to survive the warranty period.
Also there is something nice about owning applinace that were truly "made in America", when that slogan really meant something.
Just my two pence, do with it what you like.
L.