I can agree with you on that, play calling is subjective because if the execution breaks down, its hard to know if it was a good play or a bad play. If a run off right tackle is called and a block is missed and the Zeke is tackled in the backfield, then many might say it was a bad call. However, if you look at the tape and see if the block was made, Zeke would have gained 15 yards the play is not necessarily a bad call, just bad execution.
However, and I think you would agree, that there have been problems with Garrett beyond just play calling. For example, not telling your punt returner in a strong wind in New England to move up from the end zone. Like Aikman said, that is just bad coaching. Not having your best players on the field for a play your season is riding on. Why was Cooper on the bench? If the other WRs are just as good as him, why do you need to pay Cooper top 5 money? Then if the other WRs are not as good, why do you put players in the game that are inferior on the most important play of the game? That has nothing to do with play calling.
Look, the bottom line is that in 10 years as head coach Jason Garrett has missed the playoffs 70% of the time. That is the real problem here Idgit. You cant miss the playoffs 7 times out of 10 seasons and expect to keep your job, you and I both know that.