Not near as much as you'd like to believe. It takes years for us to grow up, get an education and become useful. Changing what we do can be quite difficult, especially with the time and monetary costs of doing so. Plus inroads by technology can wipe jobs quickly even if they'll eventually be replaced.

When you have a bunch of people scared that they'll starve tomorrow society will fall apart (even more than it has). The rise to authoritarianism will lead to rather bad outcomes in the medium term.