Singerguy, that's the story right there plain and simple.
I'm also at a loss to "sell" people on a vintage machine. I just sold a machine (my first!), but it was easy. The buyer already knew they wanted a vintage machine because they can better handle what she wanted to do that her newer Viking. Easy-peasy!
Today, I have someone else looking for a machine, doesn't have much money to spend and I just don't know that she's interested. She thought she would buy a featherweight from another person until she learned the price!