Agreed, plus it raises this question: why would any gaming company cooperate with an API that effectively removes their control over their assets and enables competitors and third parties from building on top of them without requiring authorization?

I can only see the "open API" benefit for free open source games. So it wouldn't have helped Vitalik and his famed WoW sword.

Then again, making fun games is hard, and there's no escaping it. So maybe it wouldn't help free games either.