Diminishing utility of Intelligence

The complaint of most of my colleagues, friends and classmates who are at work today is that they seem to be not doing enough 'value-add'. Most of us (including me of course) think that we can contribute much more. The overriding emotion is that if we could probably earn much more if only we were able to really contribute with our intelligence and learning. But then why does it not happen?
Well the answer, boys and girls is Diminishing utility of intelligence. That is as every executive contributes with his intelligence, the utility of that intelligence to the organization is quite high initially and hence the employee is recognized and promoted however as he contributes more and more the utility to the organization of that is isnt quite so much.
Think about it, could there be an explanation for this? A low level employee is usually one among many since they form the majority of the strength of the company. However as he is promoted and he rises above, the number among which he is competing becomes progressively smaller. In fact as he reaches the middle or higher management, he is among the top 1 to 5 % in any company. Now even if he contributes through his knowledge or value-add, it wont have that much impact. Why?
One explanation is that an organization can pursue only so many new ideas or policies. As a result some executives will not really be doing intelligent work but in fact will merely be implementing those ideas decided by others in the top echelons.
Another explanation is that as part of the top brass, their value add though significant is hard to measure and compare against those of their peers just as someone with $200 mill is just marginally better off from someone with $100 mill.
Thus maybe the utility of intelligence and indeed the compensation ;-) associated with it diminishes as it progressively increases per employee. I wonder if that's why they say, 'the meek shall inherit the earth'?
P.S. Special mention of RM, AK, DC and ND-M for having had contributed to this blog through your insightful comments. {This is not simply a means to flatter you but I guess it wouldn't hurt ;-) }