One Time Passcode seeds are a globally available ID system.
and I really don't call them second factor, that conflates the whole issue of where they are stored, how they are synced and used. people should be able to recover access to their one time passcode seed and there is little excuse for this.
TOTP is globally available, but does not have an established way of recovering your key if it's lost. ("Little excuse" or not, people will not back up the key or print backup codes.)
While if I lose my SIM card, I'll walk to one of my operator's shops (there's probably one within 1km), show them my ID, and they'll replace the SIM. It's the only digital identifier that I could bootstrap from if I lost access to everything in one go.
and I really don't call them second factor, that conflates the whole issue of where they are stored, how they are synced and used. people should be able to recover access to their one time passcode seed and there is little excuse for this.