I have only sold one thing (to a friend) and been with Etsy longer than you, so I often wonder as well what makes one thing sell and another not. I don't think you can fully rely on Etsy alone as a selling mechanism. If you check the things that sell the most at
http://craftcount.com it seems to be cheap jewellery, craft supplies and cushion covers. I suspect that the main people surfing Etsy on a regular basis are other sellers and young women who like fashionable decor. We both need to attract our buyers to Etsy somehow.
Being an exhibiting visual artist in the past, I can tell you that there is always someone out there who will like your work and buy it no matter the price, but finding them is the issue.
I also agree that having some of your originals for sale might help. You could still sell the prints. Also possibly show some of the prints in a frame (don't have to sell the frame). It helps people visualise the artwork in their home. As with all advice, this is just a maybe - take it or leave it as it may have nothing to do with why you aren't selling - just possible suggestions to try.
Good luck!