Probably because it was never designed to 'work' only to care for those that fell outside of success.
From the Holy Bible, one is supposed to care for the widows and orphans, now my belief is that the word 'widow' was used for an unmarried woman with a child - how ever she got to that status. It was the duty of the community to care for them, they were allowed to glean the fields and such. Not an easy life but still not totally starving.
I am no expert on the Holy Bible, there are many things I am still discovering, but for sure it has more to offer me than some things I am hearing from conventional wisdom.
Ever wonder why there problems in Chicago, with all the money the Democrats give their favorite causes? The little Baptist Churches do much better with less, the Catholic schools do better with less, and the list of good people doing good things in Chicago go far beyond race, political party, religious community. But it just doesn't get into the political process nor the ruling elite, they seem to be permanently corrupt, EVIL. But they keep getting re-elected by the Daly's dead voters, and no one in Chicago is surprised. That is all a myth of mythical proportions. No truth to it. They aren't evil just plain old fashioned stupid. They don't see that it doesn't work.
In America, you work and make your life, you read and educate yourself (yes, there are great and good teachers, but really you know who is responsible), you make friends, you do good things for good reasons - never for money. You invest in a future, you don't borrow with no intention of repaying quickly. You look for a mate, build a family, do more good things, and some how, you die. But the little world you built, or helped along the way, the people you touched are all better for your being there when it mattered.
You can do most of that anywhere in the world, and we will all be better for it. No one has to be wrong, do bad things, become hated, become a problem... The problem with the Great Society, is the title. It should be the humble and nice society - no capitalization, and it isn't a government program, it is a human program called humanity. Be nice out there, another million laws or so - only employ too many lawyers, politicians and criminal injustice - y'all be nice and we will git it done right.