Douthat worries about it:
The non-employed working age Americans of the 1950s were mostly married women with wage-earning partners and children at home, with meant that they were members of income-producing economic units and embedded in strong social networks even if they weren’t holding down a 9-5 job. If today’s shrinking employment-to-population ratio were mostly a post-feminist variation on that theme, driven by a combination of married men staying home with the kids while their wives work and professional women taking time off during their prime childbearing years, then it would be less troubling that what we’re seeing today. But instead today’s decline in work is concentrated among the unmarried and less-educated — populations, that is, that tend to lack precisely the sources of social capital and economic advancement that participation in an even a low-paying job can help supply.
So while a decline in workforce participation is not inherently problematic, the fact that it’s happening among people who lack other sources of community and other means of socioeconomic ascent means that it’s more likely to compound existing trends toward stratification and atomization, hardening the lines of class and making individual lives unhappier even if the economic pie continues to grow.