You're implying that there's a set "value" per employee that the companies are going to pay and they merely subtract their costs from employees while contractor

You're implying that there's a set "value" per employee that the companies are going to pay and they merely subtract their costs from employees while contractors are paid more because they lack these fees. That might be the case for skilled labor that freelances but we've seen a plethora of gig economy jobs be created that trend towards minimum wage or lower. That does not mesh with your claims