If the season were shorter the tactics would be very different and what you said might not be true anymore. For instance you might only need 2 starting pitchers. If you can have Scherzer pitch half your games that’s gonna be very different than having him pitch 1/4 of your games. There’s also the playoffs to consider as a case study. There you have far fewer games so the strategy is very different, and arguably the games are more interesting.

I don't think there is much reason to think that would happen. We don't see evidence of that in the regular season as Scherzer's career record is 190-97. We don't see evidence of that in the postseason when even the best teams will generally lose a few games. And we don't see evidence of that in baseball history when in the past a team's best pitcher might start up to half of that team's games. Randomness is just inherent to the game of baseball.