They only combined for three postseason series in that span and were barely competitive. However, that same period saw two of the greatest players of our generation on the same field at the same time - Mike Trout and Manny Machado. Of course, those two clubs mightily wasted their best weapons in their prime. In the process, they delivered some memorable games.
Cincinnati Reds and Milwaukee Brewers haven't been the most consistently competitive teams in recent memory. They have combined for just two NL Central titles in the last decade and had to go through unkind periods of rebuilding in order to reach their current places of contenders.