Ummmm. What do you think that saving and investing are?

Surely the rich guy isn't saving by stashing the money under his mattress, or he wouldn't have gotten rich in the first place.

Perhaps he's putting the money in the bank, in which case it's going to be used to underwrite someone's mortgage, or something like that.

Perhaps he's investing it in the stock market. But support of equities means that he's financing business, which is just another way of saying that he's helping to create jobs.

someone who is just scraping by having more money is more likely to result in them spending that money right now

Assuming that's true, what comes of it. I picture that person going out and buying a nice new HDTV from Sony, and much of that money going to Japan rather than sticking around in America.

Obviously I've picked my examples to tilt in one direction. But it ought to illustrate that what many people seem to believe is obvious common sense is far from that, and perhaps even, counter-intuitively, turns out the opposite.