This is a pretty good article from RAB contrasting the Cardinals and Yankees offensive approaches. The Cardinals rely on timely contact hitting, while we all know the Yankees rely on the long ball.
But different approaches yielded the same result: The Yankee offense died in the ALCS. The Cardinal offense died in the last 3 games of the NLCS - they were outscored 20-1 in the last 3 games of the series.
Slumps can happen to any team, regardless of the approach they take to scoring runs.