Great insight and reasoning why we should all use 2-factor authentication. While this now is widely spread and most of the sites offer this addition to improve security, most of us we prefer to keep things simple, even if not always thinking for security. Also, I know that the 2-factor authentication using SMS by phone can be hacked and maybe also for that purpose . Of course it cannot be easily hacked (you need some kind of device to connect to the operator network and intercept the calls), but just proves some boundary cases.
Nevertheless, we should all adopt the 2-factor authentication in order to minimize the hack of our accounts! Great pointing this up in the post.