I think they were referring to the fact that the chief reason there is not large-scale PV panel recycling is that very few panels have ever been retired. It turns out that short of physical destruction by hail etc a PV panel does not degrade beyond economic usefulness simply by being out in the sun. In fact some panels actually get more powerful. The surprising-to-some conclusion of NREL's PV Lifetime Project is that the economic lifetime of a PV panel is basically forever.