Only one person has mentioned LeBron?
Lebron for his career (as a 6'8" 260 lbs small forward with among the greatest physical gifts of any player in the league) has averaged 6.5 rebounds and 0.7 blocks per 36 minutes. This is despite the fact that he's spent number of minutes at the PF spot throughout his career. He's only averaged over 6.5 Rebounds-Per-36 four times, and only averaged over 0.7 Blocks-Per-36 five times...out of his 12 year career.
In fact for his career Paul Pierce's rebound (5.9) and block (0.6) numbers on a per-36 minute basis aren't far off that, and he has certainly never been perceived as a great shot-blocker or rebounder (albeit a very good one, relative to his position).
Even Dwyane Wade hasn't been too far off Lebron's numbers (4.9 rebounds and 0.9 blocks) when you consider that he's a 6'4" shooting guard, who has spent a significant number of minutes at the PG spot, and has been injured for much of the past 3 or 4 seasons.
Lebron is an outstanding player - one of the best ever - but he is dramatically over rated in a number of areas - two of which are defense and rebounding. Playmaking and ball handling are two others. Lebron is very good in the latter areas, but is nowhere near elite PG level (as many would have you to believe).
Lebron is basically elite in two areas (physical ability and outright scoring) and outside of these two areas it's his versatility (i.e. being above-average-to-good at lots of everything) and relative lack of flaws that make him such a special player.
The much preached story (that Lebron is among NBA elite at rebounding, passing, ball handling, shooting, defense, etc) is a false reality that the league would like you to believe about their current league messiah.