Phones could allow much higher security if they supported 2 factor authentication. This could be face/fingerprint along with a typed or swiped password. This seems like a simple solution that leverages software that is already implemented. Just make it an added option in addition to the existing one
ETA: Sorry for the duplicate posts, I was getting error messages. Pls use this one.
I think you're getting downvoted because many people don't understand exactly what you mean by 2FA, and especially, for what purpose.
You could try to clarify that, but let me see if I get this right: You'd like to use 2FA as a more secure way to access your phone, having the phone require 2 factors to unlock it; not as a way to use your phone as one of the "two factors" for some other 3rd party account, right?
Basically, you'd like a phone to support an authentication method requiring 2 factor to unlock the phone itself, for example both a PIN and fingerpring, or passphrase and face recognition, is that right? As in, one needs both factors, not one or the others. If so, yeah, I guess that could be pretty useful for the very security conscious among us.