That's an interesting idea to me, particularly regarding preservation of games of bankrupted companies. I'd still be in favor of a central registrar as opposed to NFTs, just because of the huge inefficiencies and environmental impact of that (essentially useless) computation.

There would need to be some governing authority dictating that companies need to honor the download of games not purchased from them (essentially the government of each country that has this as a law). It would make sense to me that that same government could host a service to keep track of the transactions. Or, more likely, the government just mandates the companies to play nice and exchange purchase data with each other. Sure, in some sense you're letting the wolves run the henhouse, but it also isn't that different from a game company refusing to give you a game you purchased from them. They could do that, but you would take legal action against them. Same thing here.