Idea Summary
Add a basic 2FA authentiction, screens, flows, logic to the logic process based on an authenticator app like Google authenticator or one of the many alternatives.
It should be an option.

Use Case
It is generally recommended to improve the security of the authentication process with 2FA. 
This is a widely accepted best practice.
Any Apex application that allows users to log on to the Internet should implement this.
Why not support developers with a basic implementation out of the box.

Preferred Solution (Optional)
It is preferable to use an authenticator app Google Authenticator or one of the many alternatives.