Investor dollars are not kept in a giant vault, but they are also not necessarily "being put to use the U.S. economy." If I buy $1000 of Microsoft stock, Microsoft doesn't suddenly have $1000 more to fund their projects. Some other investor gets it because he sold, and he's not necessarily putting that money to actual use either. It's all just numbers getting updated in a giant database somewhere, over and over until someone cashes out and actually spends that money to buy groceries or something. I guess some might consider those database updates and the growth itself to be "put to use" but I don't.

Almost all of that was an increase in stock price. That's about as close as you can get to just sitting in a vault. If he were selling it and using the money for something else, that would be one thing, but he's really not using much of it.

This is not to say it's his fault. That's how our laws are written. But that is the point of OP. That our policies should be forcing him to sell and put that money back into the economy.

Not sure if you’re really curious but it’s because it means the US is going from using tax to sustain itself to borrowing money (hence the ballon of debt). When your government relies on borrowing money, the rich always win no matter how you slice it because typically, you borrow money from them somehow. This reliance is the beginning of oligarchy and bad policies that strongly favor the rich from this endless cycle of debt. It’s been true for any developed nations like Four Asian Tigers and been true for nations with strong historic roots like the UK. How do you think the British “royals” sustain themselves?