I'll go one step farther. At a quick glance of the standings, no team that has had a starting QB miss time (injury or performance) has more than two wins on the season.
Dolphins, Patriots, Titans, Browns, Raiders, Saints and Panthers.
The Bengals wrecked the league with Browning for 7 or so games last year. The Chiefs still found major success with Henne when Mahomes was injured, once or twice even in playoffs. Payton still went 9-8 with Drew Brees missing many, many, many games.
All the teams you listed with the exception of the Dolphins have coaching issues, the Saints just being the worst. The scenarios I listed all have good coaches.