Beyond ridiculous
I find that when I look through the vintage Magnavox listings. "These units are selling to upwards of $1200 on eBay, here's your chance to get this for only $600!"
WRONG--They're not selling, nobody is going to pay that kind of money for something that only half works, missing a piece or two, when fine sets have been sold for $20 out of thrift stores or dumpstered because "nobody wants them". Same with vacuums of course. Old does not always mean rare or valuable. But yes, there is always the exception to these rules.