Why is it so difficult to remain on task?

I've been reflecting on organisations and their structures and how so many organisations, despite endless policies, systems and layers of management and people, still end up with so many people-related problems, such as personnel, regardless of role, with difficulties identifying problems when they first appear and acting on them; having difficulties with remaining on task for the entire time they're at work (avoidance of the boring bits of their work or the difficult work stuff or the inherited problems that are truly ghastly) or having difficulties delivering what's required. I'm wondering if hierarchical structures can support some personnel in taking little personal responsibility for doing what they're actually responsible for and for easily going off task, because there's generally someone else in the system above or around them to take issues to or to give problems over to; or to complain to about all the reasons why something hasn't occurred. And some of this can be easily supported by an organisational culture that tolerates missed deadlines, poor performers, and some staff mucking about and coming to work only to eat their lunch. By way of contrast, contractors are expected to deliver what was asked for, on time, every time, in the manner expected. They are personally responsible for their work. They are required to remain on task until their work is complete. If they don't deliver according to expectations, it is likely they won't be used again. Perhaps we need more contractors in some workplaces and less employees?