Offensive rebounding rates fell across professional basketball for years before stabilising. The decline was a deliberate trade rather than a loss of effort.
Every rebounder is a defender who is out of position
A player who attacks the offensive glass is standing near the rim when the shot is missed. If the defence secures the ball, that player is behind the play.
The cost is not the rebound itself but the seconds afterwards. A team missing two players in transition faces an advantage break, and advantage breaks produce high-value shots.
So the decision is not "do we want the rebound" but "what does the attempt cost us when it fails", and it fails most of the time.
The value of a transition possession rose
As teams shot more from behind the arc and pushed pace, the points available from a fast break increased. A break now often ends in a corner three rather than a contested layup.
That raised the price of giving one up. The same defensive lapse that once conceded two points began conceding three at a similar frequency.
Meanwhile the reward for the offensive rebound stayed roughly constant, since a putback is worth what it always was.
Long shots produce long rebounds
A miss from distance rebounds further from the rim and less predictably than a miss from close range. The ball is as likely to reach the free-throw line as the restricted area.
That reduces the advantage of size and position under the basket, which was the traditional basis for crashing the glass.
With the ball arriving in less predictable places, sending extra bodies inside buys less than it used to.
The trade is not universal
Teams with a genuinely dominant rebounder can still profit, because his individual chance of winning the ball is high enough to outweigh the transition risk.
Some teams also crash selectively, sending one player based on where the shot came from and who took it, rather than committing on every attempt.
That selective approach is now the common one, and it is why rebounding numbers alone say little about a team's intentions.
What the change reveals about modern coaching
Decisions of this kind are made at the level of expected value across a season rather than the feel of a single possession.
A coach conceding second chances is not accepting sloppiness; he is buying a defence that is set every time down the floor.
Spectators notice the rebound that was not contested and rarely notice the fast break that never happened, which is why the choice still looks passive.