Everything you've said, basically.

I don't even think the all-offense lineup would be an issue if they even defended a *little* better. They don't need to totally reboot this undefeated team's methods. They just need to exert more effort on defense-- not even a ton! just a little!-- and that's where it falls into effort and ego, as you said.

All these "Coach K is to blame!" people just need a scapegoat, and it's easy to pin it on the coach.