While it's probably sensationalistic, if you break down small differences, it's not impossible. Matt clearly believes Ross is a below-average manager. He also clearly believes Counsell is an above-average manager.
So let's say Counsell is +2 wins over average and Ross is -2 wins below average. That's a pretty reasonable place to start, right?
So if you swap the managers, as Matt suggested in this article, you'd have a four-win swing from each team. It's not that the difference between the two managers is eight games; it's that if you swapped them between two competing teams, you stack those four wins twice, all in favor of a single team.
Would reality play out that way? Probably not. It'd likely be a much smaller difference but given how the Cubs collapsed, maybe it's even larger. It's just so damned hard to determine how much of a collapse/streak is due to a manager's steadying/unpredictable presence.
In any case, I think most of us can agree that Counsell is a net positive over Ross.