I've had my Etsy shop for a couple of years and it is definitely hit or miss, but I think I have had some pretty great success, and it is the only place I sell. The things I sell quickly are modern baby quilts, more traditional quilts don't get much interest. And from my observations, the really successful etsy quilt shops sell simple, modern baby quilts.
My cousin does custom stamped jewelry and has been in the game for a few years, she started out really small and hit or miss, and has progressed to being extremely success, both her and her husband quit their jobs and they now have 2 employees and rented a studio workspace rather than doing it out of their spare bedroom. Etsy can be an amazing tool.