> How my logic has been evolving, extrapolating to, is Epic with Unreal Engine - and Fortnite as prime example - creating all game mechanics that can interact with eachother, so if you develop your game with Unreal you have access to "all" game mechanics in your game, with the option to allow users to freely import all their Fortnite skins or perhaps for a reasonable/acceptable fee per skin (if the skin copyright holder allows it; so likely not free, but then that will create the category of buy/license options of "For Fortnite only", "For up to 3 games", "Unlimited use").

For the most part assets in the Unreal store have to be modified (some slightly, some heavily) to work in another game. You don't get it for free because decisions are made for each game. You can't just download a helmet from the unreal store and it just magically sits on your character's head and works with all animations, because there's no clear idea of what a "head" is and how it should work.

There's no way a helmet from the unreal store can provide working stats for your game because health, food, armor, etc.. all vary in fine detail from one game to another.

So no, go read the link I pointed. Even what seems simple is extremely hard to do for interoperability, even if developers wanted it.

Assets in the UE store are meant to give *developers* an easy integration path, it's not designed to be a trivial integration path without development involvement.