Raw decoding is an algorithm, not a container format. The issue is every is coming up with their own proprietary containers for identical data that just represents sensor readings.
The issue is that companies want control of the demosaicing stage, and the container format is part of that strategy.
If a file format is a corporate proprietary one, then there's no expectation that they should provide services that do not directly benefit them, or that expose internal corporate trade secrets, in service to an open format.
If they have their own format, then they don't have to lose any sleep over stuff that doesn't interest or benefit them.
They lost sleep over having images from their devices looking bad.
They wanted ultimate control of their images, and they didn't trust third-party pipelines to render them well.
Not kidding. These folks are serious control freaks. They are the most anal people I've ever met, when it comes to image Quality.