Mary-Kate Olsen & Ashley Olsen Deepfake

First off, this is an earlier fake, and things have gotten much better since. Secondly, a lot of it comes down to where these is reference footage / photos of the faces you want with enough angles for it to learn to superimpose the desired face onto the video without a lot of artifacting. Third, yes, a lot of it comes down to time.

why the blur? why are some deepfakes perfect while other look like shit or you see the real face go throw the deepfake "matrix" ?
is it 5min jobs? i mean if someone worked on a deepfake video for a few months would it make it harder to see the flaws?