I think you've really hit the nail on the head there. People are absolutely happy to work dog hours on something they're passionate about, or something that is

I think you've really hit the nail on the head there. People are absolutely happy to work dog hours on something they're passionate about, or something that is meaningful (to the world, or to a company, or anything higher than themselves). But to take those same people, use them up, and then discard them... it makes them lose hope that their work is meaningful. Why try, when the world tells you repeatedly that it does not need or value you? The only people I can see being happy with this arrangement might be more libertarian minded, where the goal was never outside the scope of their own self betterment.