A billion dollars is both a lot of money and not that much money. It’s a lot of money for me and I could use it to give 10,000 families a $100,000 check with would be more than 80% of Americans earn in a year. Helping 10,000 families helps, but it’s not going to affect any long-term systematic changes.
Most people don’t really know how much things cost or how to implement big sweeping changes at scale.
For example:
What “Big City” do you think you can “just drop” 20,000 low income housing units? New York? Toronto? San Francisco? In any of those cities $500k is already basically “low cost housing”. And you don’t think there are other people profiting from real estate speculation who are also billionaires with city government connections who will listen to them when they squeal?
And even if you could, what’s 20,000 homes in a metro area of anywhere from 5 to 20 million people?