Grabbing at straws. The Cowboys rested their starters in the 90's with Aikman, Irvin, and Smith all in street clothes in finales, including against the Commanders, and that didn't stop them from winning Super Bowls.
It's easy to say it was this or it was that, just like pointing to one play and saying that's why we lost or they won. It's a 60 minute game with an average of 60-70 plays per game per team. You lose by one score or less; why you lost is a ridiculous game to play.
The only correct answer is "we didn't score enough points"
Let's also remember, that while we hate seeing Zeke off the field, he still had more touches and more plays than any other back in the NFL this season. I'm no expert on NFL bodies and careers, but just how much do you play the guy when he's already carried the rock more than anyone in the league and been used in pass protection most of the season because no one else was healthy except Morris.