The long-term unemployed as a percent of the unemployed is much elevated compared to past periods of

[progree]

1. Prime age LFPR (age 25-54) is below the pre-Great Recession levels, back to 1987

Yes, yes, the unemployment rate is at 50 year lows, but note that the prime age (25-54) labor force participation rate (LFPR) is below the pre-Great Recession numbers, going back all the way to about 1987. I just looked at the September column, starting in September 1988 through September 2008, and ALL of them have prime age LFPR's that are higher than September 2019's 82.6% number. (September 1987 matched the September 2019 number)

(in the years before 1987 the prime age LFPR was considerably less because the female LFPR had not yet ramped up to contemporary levels)

All: http://data.bls.gov/timeseries/LNS11300060
Men: http://data.bls.gov/timeseries/LNS11300061
Women: http://data.bls.gov/timeseries/LNS11300062

As former Federal Reserve Chair Janet Yellen and many others have stated, the unemployment rate is understating the slack in the labor market compared to decades in the past (as evidenced by relatively poor LFPR and U-6 under-employment numbers, part-timers who want full-time work, depressed quit and hire levels, slow real wage growth, elevated long-term unemployment levels (see OP) among other indicators).