Since people are still figuring out what makes good VR and good paradigms for programming with VR, I think it'd be likely that any design by committee API would be a disaster
It doesn't matter much in practice - most people just use Unity or Unreal, which make it easy to target any major VR system. To the credit of these game engines, it's just not that hard to be compatible these days. That's why Oculus has started to use exclusivity contracts to gain an edge.