I don't think this argument makes any sense with regard to TOTP, as Google (or Dropbox, Twitter, etc.) most certainly knows the seed/secret for your account at

I don't think this argument makes any sense with regard to TOTP, as Google (or Dropbox, Twitter, etc.) most certainly knows the seed/secret for your account at their service and could be forced to divulge it via court order. Or they could simply cough up the plaintext data sans faffing about with 2FA at all. 2FA of this sort only makes it harder for an attacker to get in. Defense against rubber hose cryptanalysis comes into play where the key only exists in one place, such as the asymmetric private key on hardware security module, or perhaps a symmetric key stored on a physically-unavailable USB key. But 2FA like TOTP does not imply encryption, even though it relies on some cryptographic primitives.