Naaahhh...we go through this every year. In fact, people were starting to project Jacksonville's schedule after week 2/3 and conclude they may finish 14-2 or 13-3.
I don't expect the Chiefs to get better and believe they've reached their peak; whether they can sustain that is a matter of speculation. Andy Reid is not known for his late season improvements, and last year's defense essentially fell apart and somehow got even worse despite already being one of the worst defenses in the league.
As the weather gets colder and the war of attrition takes its toll, I don't really see how KC is built to stay dominant. They are completely reliant on a speedy offense with huge chunk yardage plays. They may be the last team standing in the AFC, but I think it's really, really unlikely this team goes 15-1 or 14-2. Their defense alone will likely lose them at least one game, even if their offense plays decently. If the offense has a down week, this team is very vulnerable. The Patriots have almost mirror issues, except that they have a proven track record of improving defensively as the season goes into stretch time.