i agree that coaching cost dallas the game ,but not because of the spike, its because they came out of the gate unprepared and got dumb penalties and punched in the mouth. they were down 21-3 before they could catch their breath.
i think in addition to the spike....they rallied to get back in the game only to fall over themselves again and give A-aron a final chance to win.
the early penalties hurt them
their lack of defensive preparation in the first half (definitely improved in the 2nd half)
their refusal to run the ball more often which they did successfully all year and all game
end of the 1st half time mgmt
and the worst was their final drive...spiking the ball on 1st down and then running 2 incomplete passes was trash when you had a timeout in your back pocket.
when you get outcoached by Mike McCarthy, it's time to find a new job