This is precisely like the imaging standards trying to replace JPG. After two decades of vendors like Google trying to establish a new standard, I can’t send anything other than an SDR sRGB JPEG to anyone, especially to an Android user.
The current post-JPG formats may as well be called “the Apple format”, “Google image”, and “Netflix pics”. There is no practical interoperability to speak of.
I’m seeing the exact same dynamics play out with PassKeys: lip service to interoperability, meanwhile consumers are left twisting in the wind, locked out of their lives because Google can’t play nice with Apple. Or Microsoft. Or anyone else.
“Interoperability is coming” is a statement in the same category as communist dictatorships promising true socialism and freedom… you know. Eventually. Just not now. Or next year… maybe later.