I'm going to be controversial and say that Mike McCarthy didn't call a bad game. Dak Prescott played a poor game. Dak and the players didn't execute. I know I'm going to get a lot of flack for this, but watch the tape on the game.
I'm going to start with the interceptions. Firstly, another poster was showing the interception to Jaire Alexander. On that play, Dak stares down the intended receiver. If you watch the angle and if Dak were to have gone through his progressions, you'd see CeeDee Lamb wide open on a corner route. That was a good play call ruined by Dak's poor decision making.
Secondly, here's the pick six play (). Dak completely forced this to Lamb. Look on the bottom of the screen. At no point does he look at Ferguson. If he does, that's a big gain. In fact, given that Ferguson only has that CB behind him, there's a chance that could've been a TD.
Now, for some of the blame going to other players, here's the play to CeeDee Lamb early in the game.
If you watch at about the 1:23ish spot, you'll see the play I'm talking about. The route is good. The ball is a little too far, and Lamb misses it. This play and the interceptions shifted momentum at the worst times. Usually, if there's a blowout, there are a few plays where you can see the momentum swing to where it can't be regained until it's too late. This is one of those games.
As I watch the tape more, the more that I see why Mike was brought back. He actually called a decent game, despite the score. As you watch the replay of the game, the players on offense didn't execute. Mike was calling plays that Dak was comfortable with for most of the season. Dak, for whatever reason, defaulted to his rookie form. The defence, on the other hand, is a subject for another thread.