Valve essentially stopped making games because selling virtual items is so insanely profitable. Being able to sell digital rights to items and then take a sellers fee no matter what platform that item is resold on later could be a huge deal, if that's what they're building.
I wouldn't agree with that, but even accepting that premise as true, why would gamestop be in any position to benefit from this? If you're, say, activision, why would you possibly sell your digital content on gamestop's platform where you owe gamestop a cut rather than on your own platform where you get the cut? Why would you put it on a blockchain at all? Just use your own boring db.
More than that, it is taking a decentralized tech and centralizing it. The point of this benefitting GME is because it would be a market they absolutely control (so they can get a cut of the profits). What's the point of a crypto tech in that case?