Invested money is usually in things like the stock market, which doesn't directly support a company (buying a share of AMZN doesn't put money in Amazon's pocket, although it does, amusingly, make Bezos wealthier on paper). Angel investing might actually be better here from a velocity perspective, I don't actually know for sure.
Yes. Maybe not their own savings account, but in some organizations' bank accounts.
Money in the hands of the low to middle class is spent far more efficiently. [1]
[1] https://www.americanprogress.org/issues/economy/news/2011/12...
And if we split Jeff Bezos into 1000 individuals, each of which had about $200 million, and each of which spent half of it on mansions and yachts and invested the rest... would that be an improvement?
What do you think the billionaires' billions are doing? Sitting in a bank account? I think the majority of their wealth is invested, i.e. it is funding industry, which is a good thing. If we assume for illustration that billionaires will spend $1B on things like private jets and invest the rest, then if we have $1T divided among 10 billionaires, we'll have $10B spent on jets and $990B invested, while if we have $1T divided among 1000 billionaires, we'll have $1T spent on jets and $0 invested. Given that, at least for the concern of "how it's being spent", it's actually best to have the megawealth concentrated among a relative few.