The word "elite" is being thrown around too readily to describe players here.
There is gargantuan difference in offensive ability between Kareem Abdul-Jabbar, Wilt Chamberlain, Shaquille O'Neal and Hakeem Olajuwon ... and the rest of the talented scoring centers.
Ability is relative to your competition.
Hakeem, Robinson, and Ewing all played in roughly the same era.
Robinson's best two seasons:
29.8 points on 51% FG% (in 40.5 minutes)
27.6 points on 53% FG% (in 38 minutes)
Ewing's two best seasons:
28.6 points on 55% FG% (in 39 minutes)
26.6 points on 51% FG% (in 38 minutes)
Olajuwon's two best seasons:
27.8 points on 52% FG% (in 40 minutes)
27.3 points on 53% FG% (in 41 minutes)
In terms of pace, the Rockets generally played at a quicker pace than the Spurs or the Knicks.
Based upon all of the above, Hakeem was a similar scorer to Ewing and Robinson. Hakeem may have had more post moves, but Ewing, Robinson, and Olajuwon were all equally effective as scorers at their peak.
See -- 1994 NBA Finals, Hakeem vs Ewing
See -- 1995 West Conference Finals, Hakeem vs David Robinson
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A player's offensive ability is dependent on their physical attributes, mentality and offensive skill-set relative to their opponent's physical attributes, mentality and defensive skill-set.
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Hakeem Olajuwon was an elite scorer because of his elite physical attributes - quickness, agility and balance -- in combination with his elite skill-set as an undersized finesse five. His footwork and variety of low post moves which allowed him to create his preferred shot attempts against any defender.
David Robinson was never an elite scorer because he failed to refine his post game. There wasn't enough variety in it. It was too predictable. He was too dependent on his jump shot and turnaround J. Against top class defenses, his offense could be hurt more than Hakeem's. He did have the athleticism though.
Similar issues with Ewing's offensive game. Again, heavily reliant on those two point jump shots (which killed him in the 1994 Finals) + those little jigs across the paint. Plus, he lacked elite athleticism, particularly quickness, so top class defenders with elite athleticism (like Hakeem) could bother him.