I get the feeling that you're winging the specific numbers because they're spectacularly incoherent.

But anyway, the United States is extremely rich and has essentially no big problems that can be solved by a small amount (say, a few billion) of money. The problems are either so big that it would take trillions to solve (supporting aging population etc), or blocked by something other than money (politics, regulations, etc). The big problems that can be solved just by throwing a few billion at them are solved quite easily by either the government or by private entities like the Gates Foundation.

In practice, it seems that politics generally takes precedence over problem solving. If you look into the psychology of it, neither politicians nor voters are really incentivized to solve big problems. This is especially true for big problems that will take more than an election cycle to solve.

It seems to me that it would be easy to support an argument that suggests more big problems could be solved if incentives were better aligned toward problem solving and if competent people, not professional politicians, were chosen to solve them.