Yes, I'm surprised that more shareholders and more of Congress haven't been calling both for Dennis Muilenburg's head and the end to self certification.
It might make everyone feel better if he was fired, but little else. He became CEO one month before the first fuselage was completed and six months before the first flight, having been in charge of the defense unit. Perhaps a better but less satisfying target would be Ray Conner (https://en.wikipedia.org/wiki/Raymond_Conner) who was head of commercial aviation from 2012 to 2016, or perhaps Jim Albaugh, his predecessor. Crucial engineering decisions would have been made during these years.