the question remains if other platforms and services do not use this and stick to google authenticator and authy, what choice do we have as end users?
As far as I know, the platform/service doesn't even know what 2 factor authenticator app you're using. So this shouldn't really be a problem to be honest. You could probably even use a 2FA app you develop yourself(if you know how to, of course).
(correct me If I'm wrong, though I'm very sure of this.)