Because it's easier to blame some external force for your problems than take responsability.

Great point. Here's an example from running a nuclear submarine. When things get complex and tricky, one of our favorite responses is to add a layer of supervision. For example, when navigating in congested or shallow water we add a "navigation supervisor" (NavSupe)between the quartermaster and the officer of the deck. His job is to supervise the quartermaster who keeps up with the ship's position and anticipates forward movement. The problem is that this frequently doesn't make the ship safer. The quartermaster is now removed from the OOD so they don't talk directly to each other like they normally do and the NavSupe doesn't bother himself with the details of the plotting. So the guy with the most intimate knowledge of what's going on (the quartermaster) is pushed a step away from the guy giving orders about where the ship is going (OOD) and replaced by a manager. Adding layers of management doesn't make things better, making the process better makes things better. and accountability.