Today, there is a large segment of what should be the working population that don't have regular employment. The jobs have gone away, as the US closes factories and businesses good paying, long term employment is just not available. Most of these people are not counted as unemployed as they do not or no longer receive unemployment pay.
This podcast is inspired by this paper from the Whitehouse Office of the Preident.
https://www.whitehouse.gov/sites/default/files/page/files/20160620_cea_primeage_male_lfp.pdf