That's fair, but even then, you are trading away around 5 seasons that would total around 12 to 15 WAR for two seasons of what you hope to be 8 to 9 WAR. This will likely shorten your competitive window and there are no guarantees that adding a Realmuto (or any other player) brings a World Series or significantly increases the chance of winning a World Series because chances of winning World Series even if you are the favorite entering the playoffs is still generally around 20 to 25%.