Teams made of people of similar level perform better than mixed teams.
It’s better to have a team of 10 people with average intelligence and skills than to mix a team of 7 average and 3 high intelligence.
The average people team could have a high intelligence and skill person as a temporary guest, but not as a member. Thus, the team would perform much better.
It’s also better to have a team of people with stellar intelligence and skills together instead of mixing 7 stellar mind with 3 average.
Lonely stellar intelligence and skills are dangerous for any team, and are better kept away from any effort that requires collective discipline to succeed. Unless they are in only temporary or with a consulting role.
Simply because People with same levels of intelligence and skills go better together, therefore performs much better.
A colony of a million dumb ants outperform a population of one million humans with disparate levels of intelligence and attitudes.
A country growth depends foremost on the skills of its population but far more on how they are organized in clusters.