I think that healthcare screws the stats badly
As I read it, you're including healthcare/health-insurance spending in that 30%, but as others have noted our system is outstandingly inefficient -- much higher spending and notably worse outcomes (measured in terms of life expectancy, infant mortality, years of healthy life, etc). I.e., rather than look at outcomes, and in particular outcomes for the poor, you just swept it all up into "communal welfare spending" and called it good.
If instead you look at our outcome metrics, and pick some other countries with comparable outcomes and split our medical spending into "proportional to results in a well-run system" and "pissed into the wind", about 2/3 of our medical spending is "pissed into the wind". That lops about 12% out of our 30%, giving you an overall of 18% which is well below the median.
And yes, I know that faith-based microeconomic handwaving (*) says that's unpossible, but that's what the outcomes are. An alternate explanation that is not necessarily more charitable is that you have laundered gold-plated healthcare for people like me (top 2-3%) into "social welfare spending" therefore medical care doesn't suck for poor. You really need to do better than this -- this looks a lot more like shilling for a particular POV than honest analysis.
(*) do we have independent utility functions? we do not, therefore the proof of general welfare maximization does not hold, and that's just one preconditions out of several that fail. All those mathematical symbols in econ papers are so much fancy wankery if you don't deal with the behavior of real-world humans.