I don't think GP is joking in that context. They're probably not implying that all younger people are not going to be able to read it, but it's certainly going

I don't think GP is joking in that context. They're probably not implying that all younger people are not going to be able to read it, but it's certainly going be a non-zero amount. The introduction of computing systems has done incredible things with normalizing representations of the written language. Most text read by all people today are confined down to a small number of typefaces. There is far less exposure to the diverse variety of even the non-cursive written word that is unique to each individual. If we have a population that not only no longer learns how to write in cursive, combined with the fact that they hand-write disproportionately lower than their previous generations, I think we're going to be surprised by its side-effects.