The very short summary of the article is that the bulk of the employees in an organization are Stalwarts, a group of people whose motivations and goals are very different than the much smaller groups shown in the corners of the diagram. Managing this group effectively and keeping them engaged in the organization takes effort and strategies that might not work for other groups.
One reason I found this so interesting is that it rings very true at a place like the University of Michigan, and I have found the pace and culture to be very different here than in the conventional business world (or at least the telecom segment of that world).
The only part of the post that didn't match my own experience is the last "myth" the author debunks - Everyone wants to me a manager. My experience has always been that the strongest contributors on the team enjoy building or operating part of the IT ecosystem where they work, and while some choose to do that by playing a leadership role so that they can influence the direction via their decisions and setting priorities, others play this role by building the systems that feed into the overall picture. And so I have always seen very strong contributors who have no desire to manage a group, and, in fact, in some case I thought they would be a disaster as a manager.