People changing jobs would really not mean unemployed, as they are changing jobs not just loosing them. When their job is replaced, is why we have regulations such as unemployment insurance. This lets people reeducate, unless even the jobs they can get reeducated into are leaving for China and India. This is one of the regulations that we simply must get rid of, if we abide by the Rand opinion.
This brings me back to the points you said you would come back to, when you have more time. Where would the mid level jobs you are talking about come from and where are they now?