My thought was, "I bet $100 billion is actually a pretty decent chunk of the US welfare state". Turns out, that's about as much as is spent at all levels of government on housing (primarily direct subsidies, legacy housing project upkeep and funding for newer tax-credit housing construction).

Then I wondered, "what kind of tax could cover that cost?" and I found a list of net worths and saw that about 5% of the wealth of the top 20 US billionaires covered that entire spending for a year. There's much more compelling comparisons to be made but I didn't have all day.