Tl;Dr the protocol requires there to be trusted token providers that issue the tokens. Who do you suppose are the trusted providers in the Google and Apple implementations? Google and Apple respectively, of course. Maybe eventually there would be some other large incumbents that these implementers choose to bless with token granting right. By its nature the protocol centralizes power on the web, which would disadvantage startups and smaller players.
OpenAI on that enshittification speedrun any% no-glitch!
Honestly though, they’re skipping right past the “be good to users to get them to lock in” step. They can’t even use the platform capitalism playbook because it costs too much to run AI platforms. Shit is egregiously expensive and doesn’t deliver sufficient return to justify the cost. At this point I’m ~80% certain that AI is going to be a dead tech fad by the end of this decade because the economics just don’t work now that the free money era has ended.