Seems obvious to me that jobs which primarily require research and thought will be the first to go. The job of a good exec is basically: 1) research the market, 2) make presentations, 3) make high level decisions based on research and input from others and have leaders below you work on those. Ok, 4) is schmooze and maintain relationships but you have an org to do that too.

C-suite are there to protect the owners so they don't get in trouble if their company breaks the law. That makes them the most important position. Being a good manager is just a bonus.