You still don't understand how this works. Apple can't complete the provisinig process alone - the user unlocking the keybag on the device with their password

You still don't understand how this works. Apple can't complete the provisinig process alone - the user unlocking the keybag on the device with their password is an essential part of provisioning a device. When a new device is added to the keybag, the other devices report the change - this isn't controlled by the server and isn't optional. Apple can control the transport infrastructure, but they cannot enrol new devices into the cryptographic session without the user being involved.