2 of those teams are actively tanking, and the Broncos could soon join them.
I don't know what to tell you. The Browns absolutely crushed a bad team like the Jets, and they beat the breaks off of Baltimore in Baltimore. Just because the 49ers had 2 weeks to game plan a team coming cross country, whose weaknesses perfectly match your strengths on both sides of the ball is and should not be an indictment on the team.
The talent on the team, whether well coached or mentally checked in or not, will see them to at least 7 or 8 wins with comfortable ease.