Employees are not trained or promoted with any realistic expectation of genuinely rising through the ranks, at best they will be rotated.
Mid and upper level managers tend to be brought in from the outside. As you would expect, as anywhere, insiders use their positions to protect and promote themselves, to get keep as much of the rewards as possible.
Management agrees to allow benefits for the masses to placate them so that they can corner an even larger slice of the pie. Anadarko is in a weakened state because of brashness and arrogance and little stupidity, not just because of market forces.