I think it just says that taking a degree is more common than in the past - if you have the smarts for ATC you likely have the smarts to do a degree.
My take on it is for ATC you need to be a good generalist - fairly good at lots of things, not just excellent at one or two. Probably why the tests have trouble - spotting strength focussed in one direction is comparatively easy. Your average corporate psychopath is an easy pick.
Maybe explains why they end up in ATC - they don't fit into a standard employee shaped box.