Shot blocking always depends of the opponent player/team and his/their skills (jumpshot, range, insideshot), so if you look at your outside- and insidedefense ratings against your opponent you can see why you do not make so much block shots (in the moment)!
in team ratings, you cannot argue with that.
the point i'm saying is that in real basketball, there can be instances wherein you wouldn't defend on your main man. in BB, you could do it 48 minutes per game.
either my player just backs off slightly or gets close, you never see that driving SF getting away to his defender and ending up being blocked by my center.