Not sure, maybe not. There are probably incentives in terms of playerbase, depending on how big these NFTs are. The NFT holders could also voluntarily fund the cost of integration, as it adds a "use" to their NFT.
My point was though that interoperable game assets aren't farfetched, they already exist.
We are talking a couple of hours per NFT - and ongoing work and testing.
There's a reason most games only have a few outfits or a handful of cars players can choose. Every model, skin and so on is a pile of regular, ongoing work.
Even SecondLife required per-model import work, rigging, custom scripting, etc.