As far as the QB situation, they did score a lot of points after Cutler went down.
Because of Devin Hester turning on god mode for a return and Matt Forte being lights-out (and even Forte would have had 15 rushes for 41 yards if you take away his one monster rush). McCown's play was basically Kyle Orton -- good enough to get through a game but not enough to win it on his own, and that was against a defense that was asleep at the wheel and gave up 300 yards in the second half.
I do not see good things happening this season.
Good to see Smith found a groove out there. Maybe getting the boot from SF was exactly the kick in the pants he needed to pull it together.
Smith has a decent completion percentage, but 7 TDs against 4 INT, and a 79.3 passer rating. That's not exactly a "groove" -- it's mediocre. In fact, it matches his career stats almost precisely
(lifetime passer rating: 79.2). The Chiefs are 26th in the league in overall passing yards; they're winning because Jamaal Charles has been very good and the rushing defense has been obscene
. Alex Smith is by no means the reason Kansas City is undefeated.