OK, but is that the only possible outcome? What if a bunch of them went for 2 yards and we punted? That's certainly a possibility is it not? An average is an average. It doesn't mean every carry will go for the average.
The arbitrary request was meant to be somewhat serious. If one carry isn't enough, what's "enough"? It's a quantity measurement after all.
If we're talking about something like a mode, which is how frequently something occurs, 56% of designed running plays went for 5 yards or less. So the most likely outcome in a run-heavy drive with 11 minutes left is you'll get one chunk run of 15-20 yards, and then you'll get a bunch of runs around 5 yards or less. Need 72 yards for a TD, so pretty much best case scenario is it'll take you 5-6 minutes to score a TD, and that's assuming you're highly efficient in the red zone, of which that hasn't been true barely ever. So realistically, 7-8 minutes to get a TD. If you even get one.
Of course then the question is... do we get the ball back? It would appear unlikely, given that once we turned it over, Browns were able to run 10 more plays and over 5 minutes off the clock, while barely moving the ball at all. Had the defense been able to make a stop at some point really, could have gotten the ball back with maybe 7 minutes left instead of 5, which gives you a shot at another possession.
Would also point out that as "dominant" as the running game was, the average run by either Dobbins or Edwards netted us about 1 additional yard per play than the average Huntley completion did (on a day where he was quite bad).