50% doesn't seem like too much of an exaggeration
There are literally like 150+ pitches a game that all involve a strategic decision to be made. Defensive coaches position players individually from batter to batter, and sometimes from pitch to pitch. Players and coaches together make split-second decisions on whether to take extra bases on base hits. Fielders make split-second decisions on whether to try to squeeze extra outs, get the lead runner, etc.
Yes, it's a gross exaggeration to say that the 0-1 times a game where you have to decide whether to pinch hit for the pitcher - is 50% of the strategy of baseball.
