Well the Google Authenticator application is just an implementation. I can use any TOTP generator to get access to my Google Account, or alternatively if I use the PAM module they've provided, I can use whatever I want to generate my codes to log in to my Linux machine. It just so happens that they use this mechanism for their two factor auth for Google Accounts.

I definitely hear you on the better user/dev experience. That's very clear from the variety of methods and slick screenshots they've got.