Well, that's patently untrue for the game stores I visit. I've been talking from experience there! I.e. the kind of people that enter the shop while I've been there playing something.
I have to conclude that game stores look quite different in the US than they do here in Germany. Typically, the store front and entry area is mostly dedicated to mainstream board games, novels, and maybe video games. There's also often a pinboard and/or posters to advertize gaming groups and tournaments. Depending on whether or not the store carries LARP stuff or crafts and arts materials there may also be an area dedicated to it.
Behind the counter you'll find the stuff like CCGs, sleeves, dice, etc. If you are interested in RPGs or miniature based games, you'll have to enter the back room. Unless there's a dedicated area for playing tournaments that's also where the gamers playing in the store hang out. It's possible that the back room 'may' resemble what you are calling a 'man-cave' a bit in some stores.
What your description reminds me more of is comic shops. But these don't typically have (m)any games for sale. They may carry a few rpg books, as well. But apart from comics their focus is on merchandize and collectible items, e.g. Star Wars miniatures and the like. Also, they don't have room for gamers.
