A couple of thoughts:
Arrowhead is one of the oldest stadiums designed for football. Outdoors with natural grass it is a nice venue. After 40 years it got some renovations recently. Stadiums are the least expensive if you build them well and have them last a long time. The Chiefs ownership has been smart about that. It has been a tough venue for opposing teams.
The Chiefs have a nutcase GM. When first hired he fired the entire scouting staff. I said it was because he didn't know any of them. I'm sure at least one of them was competent and would have been liked by GM Pioli.
I could tell from the preseason game that the Chiefs were not a talented team. It was more than just not having a good enough QB (Pioli's boy Cassel from the Patriots, Pioli's former employer).
After the Packers Preseason game the Chiefs first two games were big losses 41-7 to Buffalo and 48-3 to Detroit. The Chiefs were not ready to play after a crazy offseason without workouts.
You can debate firing the head coach of a 5-8 team. But you knew that Pioli would put a former Patriot, Romeo Crennel, in as interim coach. To me it appears that Pioli is making an attempt to hold on to power. He probably would not have liked what Haley would say in his end of the season report to the owner.
Pioli has been with Belichick from Cleveland to the Jets to the Patriots. Going to Kansas City on his own he has not been making any friends. The lack of stability at the franchise has hurt the morale.
I don't think the Chiefs will be a good franchise until Pioli is gone.