The only place he's ever really been dumped was Denver. Chicago traded him for Cutler who, at the time, was considered by many to be a top 10 QB coming off a huge statistical season (arguably the best of his career) after only 3 years in the league. The thing in Denver was complicated and weird.
Don't misunderstand, I'm not declaring him a franchise QB just yet, but I don't think his history precludes that. He's shown to be the kind of guy who gets better with practice, and if he shows to be a top 20 QB I think we could be legit contenders for the next several years.