My friend Larry is such a person. He's 48 years old and has worked for Wal-Mart for 25 years, mainly as a cart pusher. He has Down's Syndrome. He does get support from social services however, they have someone helping him manage his money. Due to his longevity at W-M, his pay is about $16. per hour. He shares an apartment with another Down's Syndrome person and social services people pay their bills...out of their own money.
When Larry takes a vacation, that his employer forces him to take, he hangs around the store and his supervisor has to keep him from working voluntarily. He says that W-M people are his "family"
What a contrast to all the fakers out there on the tax payer's dime.
It is because the schools get a ton more cash for each one, and the parents get a gov check for them. The schools even have names of doctors to sent them to that will confirm whatever is required.