Linux

There was an abstract conceptual theory of system agnostic game add-ons. It isn't... completely inconceivable.

You could work with a relatively prolific engine, like Unreal, and set up a standard character model dummy with designated hard points for attaching accessories and certain default movements. Then any accessory could simply scale to the environment - Master Chef could swing a keyblade while the Elden Ring guy gets to wear Iron Man armor, because these are all "human" models with well-defined structures that could map to the associated equipment. The blockchain becomes a universal registry for these assets that a platform can read from to render the art.

The problem is that nobody ever actually implemented this universal protocol. They all just ran off making jpegs of weird animals and running fake auctions to create the illusion of a secondary market. You had zetabytes of data being processed so some Baked Alaskahole could claim his Kumming Koala was worth $40M.

I don't even strictly begrudge "the blockchain" as an idea for licensing and data storage (just please don't ask me to think about who is generating the licenses or storing the data). But it was all vaporware. None of it was anywhere close to being created, much less delivered. People were throwing billions with a b of dollars at entirely empty promises.