Call it sufficient demand. Put simply, an economy cannot fully use its human resources unless there is enough demand for all the goods and services the people produce. Right now, aggregate demand is brisk in the United States, but do not count on it staying that way. American consumers are going deep into debt and Asian economies are in a mess. Governments in every advanced nation are shrinking their deficits, which may be fine for the long term but will further crimp demand.
Central bankers continue to be way too fearful of inflation.
Business flexibility without labour agility means a lot of jobs, but many of them will pay little. Labour agility without business flexibility means a lot of over-qualified people for jobs that do not exist. Both without sufficient demand still means too many unemployed. No nation on either side of the Atlantic has got it completely right. There is a genuine third way, but it is hard to accomplish.