In scientific terms, a black hole is a piece of space with a gravitational pull so strong that nothing can escape from it. The Dallas Cowboys have fallen into a black hole of their own so powerful that the rest of the defense has been drawn into its grasp, unable to escape for almost a decade. That black hole is the cornerback position.
There is no position at which the Cowboys have thrown more resources than corner. An NFL team has a finite amount of collateral, be it salary-cap space or draft picks so if an overabundance of the team’s equity is repeatedly absorbed by one position on the field, the rest of the team will be drawn into the abyss.