Playing effective NBA defense is more about dictating shot location than contesting shots.
To wit, here are effective field-goal percentages (which accounts for made 3-pointers being worth 50 percent more than made 2-pointers) of every NBA team for each of the five commonly used zones of the court: Restricted Area, In The Paint (Non-RA), Mid-Range, Corner 3 and Above the Break 3.
As you can see, teams are generally lumped by location on the floor.
Even the worst-finishing team in the Restricted Area (Cavaliers) shoots way better there than anyone does from In The Paint (Non-RA) or Mid-Range.
The worst team at Corner 3s (76ers) is also more effective from there than In The Paint (Non-RA) or Mid-Range, though the gap isn’t quite as wide.
Everyone except the Pistons shoots Above the Break 3s better than anyone shoots from the In The Paint (Non-RA) or Mid-Range, and only the Heat’s In The Paint (Non-RA) shots – someone is practicing their floaters – fares better.
Clearly, you don’t want to shoot from In The Paint (Non-RA) or Mid-Range. Even the best teams from those zones are inefficient relative to other areas on the court.
That’s why defending a shot that is already being taken matters only so much. The bigger key is preventing shots from certain zones being taken in the first place and promoting shots from others zones.