The only mom pops I see surviving are the ones who do lessons, some instrument repairs but most of all have a good relationship with local schools and their bands.
My personal favorite Lanier's in Mandeville, La. Randy as I kid him is as close to being an actual musician as possible, because he plays drums. Of course then he starts with the guitar player jokes.
So besides being a great musician and all round good guy I would attribute his success to school programs and area gigging musicians. In fact as a fellow musician he will encourage you to take the instrument or equipment for a test drive or two on actual gigs before you purchase. I have lived and done business in many states and have never come across someone so easy and fun to deal with.
https://www.facebook.com/laniermusic/PS: Randy never wears shoes, in fact his motto is "No Shoes All Service".
Long live the neighborhood stores.
Later,