This is a great idea. Instead of Gamestop ignoring Amazon customers, they realize that they can never win them back but they still have stuff to trade. Gamestop gets product to sell to other customers and people who sell get Amazon money.
Gamestop has about 6,000 stores worldwide. To my knowledge, someone correct me if I'm wrong, Gamestop is the leader in market share for video games. Walmart doesn't care about Video Games, they sell them because they want you to buy grocery and apparel. They get you in the store, hoping you buy...
I don't know how your system calculates it, but if you are pulling from inventory pre-orders are not counted as available inventory (if I search internally other stores will show 0 for a game when I know they will have a few for pre-orders) until 48 hours after release.
Our store got 13 on Switch