Except the phone is thinner. It's a compromise issue, most likely the thinner phone required a thinner lens (or there's less case covering the lens, which was more prone to flare.
The quality issue is really with the photographers, though.
Bad r&d and qc then. There are other devices just as thin and don't have this issue. Apples camera has always been rated great and better than most of the competition. They have really been dropping the ball.