While I like the idea of a made-in-America knife store, it would be well worth considering adding high quality knives foreign countries. For budget knives, you could carry Moras, Opinels, and Svords. Nordic knives in general would also be well worth considering. In addition, there are many skilled knifemakers who just aren't well known. Their prices are very reasonable, and you could potentially have small runs made just for your shop.
As someone already said, you'd need to be unique to survive. Stocking high quality affordable custom users and hard-to-find European knives as well as the usual high-end folders would really make your store an interesting destination. Add in some bark rivers and a few high-quality affordable knives, and you'd have something unique.
No experience in retail, so take this with a grain of salt. I'm just thinking of what my ideal knife store would be.