Ed Dolan suggests that claims that social safety net programs on average don't disincentivize work much may depend on the current relatively limited coverage of such programs (especially compared to the situation before, say, the Reagan administration and (hopefully soon to be qualified with the word "first") Clinton administration.  He thinks advocates should consider replacing many of these programs with a universal basic income.  There is a lot more one could say about this issue, but I think this is an important point to keep in mind.