Nashville,
Hello. Having done exactly what you are contemplating back in 2008 ( What a fun year to start a business! ), I can only offer my own experience. I run Wolfsong Audio LLC from my home in Dawsonville, Ga. about 30 miles out of Atlanta. Not in my home but in the garage apartment we built out for that purpose. 2 room showroom and office. We carry about a dozen brands and show what I feel to be the "best price to performance ratio" models. Speakers, Turntables, SS power and pre, tube power , preamps integrated amps. Some internet available kit like streamers, Dacs, Roon.
Time is split about 60/40 in the showroom and doing in person service calls for auditions, room tune and turntable calibration. It turns out people really like it when they can demo gear in their own rooms with their own systems and their own music.
Nearly zero overhead. Not going to retire with giga dollars but I get to do what I love and that is helping people listen to music longer and enjoy it more.
Spending time in a customer's home allows me to hear their rig and learn what they like, what performance parameters are most important to them and how they listen.
Hours can be long, travel time can be long ( I have customers all over the South and East Coast). But when a guy calls and asks about a $300 Streamer to add to his teenage grandkids TV room so they can stream music, I get a new generation of clients.
Market research is great. Exclusivity is nearly impossible. Only sell what you like. Full Stop. Offer a real audition. Read those 4 sentences again.
Best of Luck.