LightSpectra
me autem minui
State government can never be any good at welfare. They are legally required to suck at it. Many of the other things the feds do they do because having 50 states do things 50 ways is the worst way to get it done.
If the states suck at it, it's because the potential income from taxation is overwhelmingly limited by how the federal government already taxes a huge portion of most peoples' incomes.
The main problem with social programs not being handled at a more local level is that different people of different areas have vastly different needs. Like, let's say the goal is to cut down on consuming gasoline; it's fine and dandy for a very urban city to accomplish this by raising gas taxes and using that income to make more public transportation, but that would financially devastate a rural area where public transportation isn't feasible. The federal government is incapable of making such distinctions because its programs have to be very general and universally applicable.
A less significant but still notable problem is that every layer of bureaucracy is another layer of regulations and bureaucrats. So not only is the federal government worse at implementing social programs, it's also more expensive, cumbersome and slow when they do it.