I’m commenting from an IT perspective, but if you did not observe diversification in your personal investments, then you might appreciate it a bit more ever since the financial turmoil began.
When you form a project team, I’ve observed that good project managers tend to bring in people from diverse backgrounds so that all bases are covered and a good variety of viewpoints and opinions can be obtained. If a project manager is weak or feels insecure, he may recruit people with similar skillsets to him — albeit weaker — into his team so he can exert his superiority and feel that he is in control of things.
Of course, that is non-beneficial to himself and his company and it is self-serving and does not brood well for the project. A good leader on who knows his weaknesses, acknowledges them, and teams up with people who can complement his weaknesses. Having said that, the leader should still possess basic skills in his weaknesses, otherwise his team members may get frustrated having to explain basic ideas and concepts.