I think in some locales there's probably still a market for a local store selling a Pietta gun in a box at a higher price than it sells for on-line, because there is still a segment of the market that's not internet savvy, but the market is probably half what it was 10 years ago and shrinking rapidly as more and more people become internet buyers.
However, the future is bleak for any brick and mortar store that does little more than sell inventoried merchandise for cash that can be purchased off the internet for less.
There is one thing I learned a long time ago and that is that you can sell a lot of anything, and sell it for a lot more money too, if you take some risks and offer very generous credit terms. But check your customers credit worthiness closely before you give credit. People who have always paid their bills usually always do pay them unless some financial catastrophe befalls them. Even people who have a bad reputation for bill paying will usually pay some people on time, if they've bought something from on credit that they want to keep and the seller filed a financing statement on it and has an enforceable lien on it until its paid. I also learned that we good ol boy rednecks generally love our old trucks, and often own them own them free and clear even if we're in all other ways bankrupt. IAnd if you know some of my cousins, and my friends, you know they've got hearts of gold, they'd give you the shirt off their back, they'd still stand up for America right by you today, and they'd be the guys you'd want in your foxhole with you, and you'd really like em, man, but hey, I have to admit that a few of them are not the greatest credit risks. But if they think you're going to take their old truck if you don't get your money, I'll bet you'd get paid. Of course it takes a certain amount of moxie to collect money. Not everyone can do it well.
Somebody else mentioned a black powder shooting range. I'd go a step further and say that if you could sell a black powder shooting experience, with you as the expert in all things black powder, you might have something. Teach black powder classes, show em how to load em, show em how to clean em, offer them a shooting range, credit a certain amount of time they spend shooting on the range toward the price of your high priced guns. Nothing is guaranteed but things probably aren't as hopeless as you think.
One thing that never works though is knocking somebody elses business who's also trying to make a buck.