I really don't agree with this. I think a lot of people can be exceptional alone, if they direct their efforts towards that, more so if they have coaches, support structures, etc. But it similarly requires a kind of intelligence and the same levels of a different kind of effort, to work effectively with a group.

It's a kind of collective intelligence, almost like trusting your arm to always throw the ball in the way you have practiced, you have to trust that your team mates will be able to compute or think or calculate in ways that you simply don't have time for, or don't know how to know how to do, because there aren't 10 yous, and even if there were 10 yous, you'd probably be blinding yourself half the time you try to lead yourself.

The difference between a good director / lead / manager and a bad one is stark.

I don't think it's hard to turn a single person into a star. I think it's really hard to keep people motivated on a unified goal, keep all those people thinking about what needs to be built, while none of that thinking contributes to egocentricity, passive aggressiveness, defeatist attitudes, etc. There is so much conflict that creates tiny little cracks through an otherwise solid foundation of skill, but all those cracks can add up. Do you spend that five minutes solving a problem with your SAP coworker or do you spend that five minutes grabbing coffee and grumbling to yourself about what an idiot that guy is? For people who are aware of the cracks and go out of their way to fix them, instead of stampeding over others with their supposed skill and intelligence. I mean I would be an idiot if I ignored all the times my ego got in the way of my success, and I would likewise be an idiot if I ignored the fact that I must be aware of all of my social inadequacies, and I must be willing to continue to learn from them, if I actually want to succeed.

Working in teams is completely different from working alone, and working in teams is more than being able to do your part. Working in teams while programming is being psychologically extremely close to all your teammates, whether you realize it or not. There's some stuff that you just have to be able to sync together with and then discard, without even really realizing what happened. Half of the things people wind up arguing about, those things wind up being hilarious when looked at in retrospect, if they are overcome. It's hard to even understand how one could both simultaneously suppress and ignore their social emotional connectivity while acting as though it does not exist, when it clearly does. We like to think we are these efficient, effective, calculating machines, but we aren't. This is a big reason as to why work experience is more valuable than intellectual or educational experience.

I really think the mediocrity of development occurs with otherwise extremely intelligent people, people capable of solving huge variation of technical and conceptual problems, it comes from those people continuously thinking that it is their intellectual and technical skill that needs to be constantly improved and updated, rather than confronting how much time is literally wasted on poor communication, difficulty resolving social conflicts, and rolling your eyes at every motivational, team building activity. You either like the people you work with or you don't, and some people are unfortunately very dependent on jobs they chose out of necessity, rather than jobs they chose because those jobs and those people make that person happy. Whether you cut people some slack when they need it, you apologize when you make mistakes, or you ignore those things and act like a mini tyrant, these things make big differences. It's often not when we are at are best that determines the success of a team, but much of the time when we are at our worst.