Unless you are looking for a hobby/job to close out your career, I would not envision owning a B&M HiFi shop as being a lucrative business venture, and particularly in a smaller community within 30 miles of a larger community where there are already three incumbents.
With the abundance of product information and reviews available on the internet these days, direct-to-customer sales, and manufacturers willing to allow 15 to 45-day return periods, the B&M business model is mostly obsolete. Exceptions might include locations in major cities where the buyers have more money than time, and companies handling a significant amount of internet sales that also have a physical presence such as Upscale Audio, Tweak Geek, and a few others. The model you remember from previously would be very hard to successfully replicate, IMO.
I stopped going to our local shop years ago (metro area pop. 250K+/-) when I realized that I would have to choose from only two or three brands, and that I typically knew more about the products than the salespeople, who seemed to mostly know only as much as their distributors had shared with them and about only the products they carried. The shop eventually closed over 10 years ago.
With the thriving music and recording industry in Nashville, there may be other types of opportunities for rewarding work. Maybe hook up with one of the companies that provides/maintains professional concert and recording equipment.