Two-factor authentication is a great and secure mechanism. One caveat is that it is not built on a technology that has flaws, such as the mobile data network that the author emphasized.
But 2FA mechanisms, such as Google Authenticator, are more secure because they are not tied to SIM cards or other identifiers that can be "cloned". Even if you make a backup copy of the phone with, for example, Google Authenticator, and then restore the backup copy on another cell phone, you will not get access to the data of Google Identifier. more precisely, you will get a working application, but without the data of accounts to which you generate one-time dynamic codes.