For example, in the streets in the UK we have signs saying things to the effect "don't litter", "don't let your dog crap here", etc., and there appear to be lots of folk that can't even get that right.
Anecdote: my elderly aunties friend is about 50 and mentally disabled; her speech is very difficult to understand and she has problems with anything beyond simple concepts. Her memory doesn't appear to work well. Until recently (her mother died and she's no longer capable of doing the work) she worked in a department store cafe clearing tables and doing some cleaning - she did the work set as long as it was clearly communicated and she did it with a smile. I'd guess that any member of the population that can stand and dress themselves could have done that job.
It's not much of a life clearing tables.
What exactly are these skills they lack that are needed in order to get work? Putting together a sandwich? Stacking boxes of food on a shelf? Putting dishes on a table and collecting them after they've been used?