Very different grade distribution - Routes vs Boulders

Adam Ondra and Chris Sharma have done 9b+ and the total of guys having done two grades lower in 2013, i.e. 9a+, is ten and further more around 60 guys have done 9a or harder. This means that the top guys forms a rather pointy pyramid explaining how much harder one grade is in quantitative terms When it comes to bouldering, the distribution for the hardest grades are the total opposite as around 40 boulderers have done 8C and the total number of guys having done two grades lower, i.e. 8B are several hundreds. Some ten years ago, when the boulderers started to establish 8C, the pyramid was also pointy but since more and more guys almost every years are just making it wider. One explenation of this is of course that we have gone from inflation to deflation on the top level but that it is still some inflation going down further down. It seems that the 8C boulder level are very wide and probably some of these boulders are in fact 8C+. Any other theory?