I am confused by your argument here. I am referring to total team construction.
He's saying if you have the exact same teams otherwise, but one has five 3 WAR starting pitchers, and the other has three 5 WAR starting pitchers and two replacement level ones then the 5 WAR team will have a huge advantage in the playoffs. Which I think is pretty reasonable given the success teams with elite #1 and #2 starters have had in the postseason. It's of course no certainty and you have to have a decent team to back it up, but a number of teams have either made the WS or won it based mainly on the strengths of an elite TOR and solid bullpen. The Giants being good examples recently.