Of course the world is full of average people. They have to wind up somewhere. And organizations full of average people are never going to be able to take the advice to work the superstars.
I'll believe that the slogan invest in your best has been internalized by our society when we devote serious resources to making sure that people with IQs in the top 1% stop dropping out of school faster than people with median IQs do. Anyone care to give me odds on this happening in the next 20 years? I'll take the "No" side.
The reason why is because jobs that are likely to use the abilities of a high IQ person generally require a high school diploma, and frequently require a college degree. Therefore denying these people an equal opportunity to get those credentials limits how effectively society benefits from their abilities.
Also I should note that the matter is personal. I have a good IQ and yet I came within an inch of failing to complete high school. Were it not for a teacher named Bernie Bowker, I would not have graduated, gone to college, or had any prospects of getting jobs where my abilities would be useful. I think that that would have been a tragedy, particularly for me.
Caltech is perhaps most known for this problem, with graduation rates that were <85%, but changes were made to stop people from "flaming out". Harvard has a 98% 6y rate -- University of Oklahoma is 64%