Labor participation rate is low because of long term demographic trends. Also the labor wages have been stagnant for last 30 years (adjusted for inflation). overall the benefits of increased productivity from automation has only gone to the upper decile of income. to make ends meet people are just working longer hours.

Also, there has been a fair bit of gaming of how the unemployment numbers are reported so some of those stats dont really represent what they intended to originally. if interested, John Williams of shadowstats does a good job of compiling numbers old style.