Actually, they sell surprisingly well. I find them at church rummage sales, etc and always have a few listed, Nice when they are nicely/professionally framed and when there are several in a group i.e. spices, flowers, animals. People like to have a set.
At a recent auction in Milwaukee, a box of unframed cross stitch samplers from 1930s 1940s sold for $100! So they are popular.