I need someone to sweep my streets.
No, you really don't. That job can and will be handled by inexpensive machines soon. In our current free market economy, those would be street sweepers have no real value at all. If they did not exist at all, society would be no worse off. The best that we can hope for under capitalism is that these people are quietly and humanely sterilized.
I say this entirely tongue in cheek, as my oldest son will likely never amount to more than a drain on our family and society (He is autism spectrum). In yesterdays world, he could have gotten a decent job in any of a number of blue collar industries. In todays world, he might make ends meet working at McDonalds, In the world of 2030 and beyond, there is no job that he will be capable of doing that it wouldn't be cheaper to have a robot do. So the question now becomes, if he has negative value to society, what should society do with him? (Notice I am not asking what I should do with him, I don't really have a choice in the matter.)
No amount of teaching him the difference between winners and losers is going to change the fact that in the world of tomorrow, he will be a loser, so why not let him have a little happiness now.