Make game shopping fun. Don't focus on upselling/diverting customers to used copies. Just create an environment that is comfortable full of knowledgeable, non-awkward associates who know gaming's history and its present. Remind them to check their egos and their biases at the door, and simply be good salespeople that have the consumers' interest in mind. Conduct regular tournaments, and not just for Smash or Mario Kart. Speedrun tourneys are also fun. Do cosplay contests or DIY craft contests, and don't be afraid to advertise these to the local public. Be a cultural entity and rise above the standard model.
Reward customers for their used purchases and still make a killing reselling to the next. Have a buyer's reward club where any 5 new purchases gets you a free used game of any value.
There are plenty of ways to create a sustainable marketplace. The fact is, gamers are rabid consumers and place like Gamestop and Toys R Us just aren't taking advantage of that ecosystem to its fullest. It takes work and dedication and energy, but it can be done. The key is the staff. Hire well. And no, that doesn't mean the same thing as pay well. The right job with the right atmosphere will make many a great employee accept a standard or minimum wage to be part of the show.
I love going to my local game store, it's like walking into a little museum with games and systems dating back to the snes. They also sell tons of game related toy and collectibles as well as board games and of course lots of Pokemon stuff. The people there take the effort to know their regular customers and I don't even have to call to reserve a new system or game I like. They called me to let me know they had a Switch reserved for me.
Unfortunately the store is too small (or too full) to hold tournaments yet it's always fun to browse through old games or talk about upcoming releases. Plus they help track down limited run physical copies.
It's fine when the big electronic stores pull out of video games, and give the attention back to specialized stores. Games aren't even cheaper at best buy or wal mart, I don't know why anyone would go there over a store that actually knows about games. A good shopping experience is more than putting a bunch of boxes on a shelf.