Shirley does have a lighter feeling to it than something like
Mildred or
Beulah, and therefore I think it has a better chance of being picked up again. Also, with the interest in all things vintage, I think that helps her chances as well.
Shirley screams "slightly lumpy retro" which many people appreciate for their lumpiness (like me).
I don't think it will ever rocket up the charts and take a place in even the top 100, unless there is some glorious
Shirley who comes along and charms the public again, but I wouldn't be surprised if it had a modest creep.