Out of curiosity I went and looked to see what the numbers looked like.
Memphis led the NBA this year with 14.1 ORPG. 17 teams were in double digits and 28 were over 9. Philly was last at 8.5
A decade ago, Chicago led the league with 13.7, but 27 teams were in double digits and one more was at 9.9. Boston was last at 7.8.
Without doing the math, it looks like there's a slight decrease.
Going back to 2003-04, the first year for which the stats are available on the website I found, you can see there was a greater emphasis on offensive rebounding. Dallas was first at 14.7, but 23 teams were over 11 and all were over 10.
NBA offensive rebounds per game, by team.
www.teamrankings.com
Not trying to prove any points here, I was genuinely curious.
Given the huge increase in 3-point shooting, I guess this shouldn't be surprising. (Every team made between 10.5 and 14.8 3s per game this season; in 2003-04, the numbers ranged from 3.0 to 8.8.; and in 2011-12, the numbers ranged from 3.9 to 10.0.) But I think it's fair to say offensive rebounding is still an important part of basketball; it's not like the numbers went from 12 per team to, say, 6.