Google fills my droid with bloatware. Even worse: all of Google apps will not work without Google Play Services which is a super abusive app: among other things, it logs ALL MY ACTIVITY 24-7. So, if Google already runs apps with such privileges, why not adding a small app that mimics Whatsapp SMS verification. After verifying that a given SIM is installed on the phone where my Google account has been authenticated, it can establish a secure tunnel to send me 2FA codes. If a hacker would clone my SIM and even have my Google password they can prevent login until I grant permission from the first install/verification. Should I lose/change my phone, Google would not allow a second verification unless a pin is entered (which I created on the first SIM verification). Another aproach that avoids the pin number would be a delay before authenticating the second install. If I get 24hrs and a notifcation that I have logged-in on a second device, I certainly have enough time to fix any possible hack.