My thinking is a bit different. Would you enjoy painting and putting together a new quilt studio? If you would get a lot of pleasure from doing that, then you might want to go for it. You would have lots more space. Gran of 6's basement studio is beautiful, and the lighting looks wonderful. I wouldn't let the worry of how long you might be in the current house factor in too much.
Of course, I have a small room, and I like to paint and organize. I don't have a basement I could move to. Basements just aren't part of Texas homes. (I am sure there is a reason for that....) But if I could get a larger room, I would go for it.