The whole point of standards is that there should be multiple implementations that can support it. Now I do agree with your point on that standards should be based on feedback from implementations but as the above comment said, this is just google making adding features and making standard documents to shift blame on other browser for not implementing them.
To be fair where are the other browser's proposals for giving apps the capabilities they need? Browsers should be shamed for not making an effort to support common use cases that apps need.
