U.S. unemployment fact

Tyler Cowen reports,

People unemployed over 6 months rose by a whopping 361k, 44% of all unemployed.

What does this tell us about human capital? If you're made redundant and don't get a new job quickly your human capital depreciates to such a degree that you become almost unemployable? Or is it that those with the lowest marginal product, and thus I guess the lowest human capital, get fired first and because of the low human capital find it difficult to get another job?