Many illiterates are illegal aliens who will never learn English. They settle in their barios and ghettos and then complain that our economy doesn’t do enough for them.
This is an issue for native ‘hoodrats as well; one problem for cities is that they offer tax breaks contingent on hiring x number of local residents, and too many of those simply have 0 job skills. Illiterate, unaccustomed to showing up for work (or anything else) at a set time...they simply have no role in this new economy, and would have been fairly useless in the old one as well.