Does "sign in with X" not lock you into X's ecosystem? That is, if I lose my Apple account or my Google account due to their judgement of my actions, have I lost access to the services I authed via those accounts? That is, if I change my email, most services allow that data to migrate to the new username. Do the "sign in with X" allow the same capabilities? (I ask from ignorance, not from sarcasm, I really don't know.)