According to my guild, to tie a quilt makes it a comforter. I entered a quilt which I was proud of--a Brown Bag Project, and I was told the judge would barely look at it because it was tied rather than quilted. I really didn't care.
I tied a lot of mine, as I don't have the time to do that much quilting--hand, and I can't afford to send them out to be machine quilted very often. So, around here to tie them they are then referred to as "comforters."
Our guild ties almost all of them we do for Community Quilts. It for sure is not a "lost art."
Mariah.