Yea there is certainly some portion of the problem that boils down tot he fact that people just dont use their negotiating power.
As someone who has done a lot of hiring lately I've had people come in so low I've literally had to offer them **more** than they ask for. I cant imagine most companies would do that, nor should they have to, typically both parties do and should be negotiating for their interests. Its just most people just find negotiating stressful and would rather not, but sadly thats just a life skill society needs to function.