SMB is basically a worst case of difficult to tame protocols. A sea of ancient crufty bizarre interlocking protocols, which Samba had already done good work reversing. But after enormous enormous bad blood, bad press, and a nearly billion dollar EU antitrust fine looming, Microsft went & did the not-immoral(court mandated thing & documented the protocol & stopped anti-competitive cutting out others. Now hypothetically others could come and participate too.
The idea that every app does messaging perfectly is indeed dubious. But the iMessage reducing outsiders to bit players, shunned, with shit experiences & not allowed to improve, is exactly the sort of monopolization anti-trust hellscape that seems like is getting turned back here.
Fear over imperfection to me is way way way way down the chain of concerns to the blatantly anti-competitive, ever-isolating, closed off intranets of proprietary, big player apps engaged in high stakes vicious anti-competitive practices, like Apple is so notoriously & vicuously known for.
It might not got smooth at first but progress will be possible & things will improve quickly from there. Market forces can reassert themselves, once interioeration begins. It's gonna be great. Dont let a fear of openness & love of the giant obstruct us for yet more decades, please. The future & possibility is too valuable to squander, too valuable to let us be divided & sundered like we have been by these vast duopolies & isolated fragmented partial un-inter-networks.