Capital isn't injected, it's hoarded.

The rich are already doing fine. They're doing better than they have since 1920. As a class, they have so much money that they're able to do stock buybacks because investing it doesn't give moneygasm-style returns. We're nearing the point where they can Scrooge McDuck-style swimming pools full of cash.

The problem with the current economy is very much not that the wealthy don't have enough free capital. Quite the opposite, really.

The problem is that they have so much free capital because they're addicted to non-productive methods growing their wealth.

Sure, but which business injects capital in te first?

I have no idea, but I'd like the powers that be to recognize that there are two economies and to prioritize the lived economy.

I first became aware of the difference when "the economy" was starting to boom in the 1980s even as we were busy returning to breadlines under the name of food banks.

I'm not sure we even need the finance economy. A pure stock market is one thing, but by the time you get to rents over profit on actual production, the financialization of housing, derivatives of derivatives and all the other distancing from actual production, it's just shell games with no benefit to society.

Your comment seems reasonable until you actually question the details:

How would forgoing a capital gains tax benefit the working public? Any answer you give will basically be "trickle down" economics, which has been proven to not work. Giant corporations and obscenely wealthy individuals hoard capital like a greedy dragon, they certainly don't inject it!

EDIT: Of course they couldn't answer that one simple question...