Zoom gets to be a partner in this because they had an ‘edge’ already in terms of having good product market fit and a huge customer base. That’s what makes them a good parter to help develop the api.
I could today create a simple video chat app, but it would be silly for Apple to make me a partner in their development process because I know nothing about the users of video chat and have no customers.
There is no benefit to the world in me just cloning Zoom, so access to a small feature refinement makes no difference.
Generally being one of the best at what you do gives you an edge because people value your experience and want to work with you.
That is fair.