The game Monopoly is a pretty good metaphor for capitalism (I, personally, am the unlaced boot), because it models the positive feedback loop. Once you own lots of property, it's easy to make money, and that money lets you buy more property off the cash strapped players. The upshot is that you usually get a slow start, then an energetic ferment in the middle of the game where anyone can win, and then a creeping inevitability at the end, as one person gets richer and richer, and everyone else get knocked out of contention.
That's a lot like real life, except here bankruptcy doesn't mean you now have time to grab a new bag of chips from the basement, it means you are at risk of becoming a street person. Also, the game Monopoly has to end when one person owns all the property, because nobody has any more money to pay them anything. But real life doesn't end. Instead, the winners keep sucking in wealth, trickle out a little charity, and hand to their kids ownership of the railroads and Park Avenue. This, historically, is how it's worked (see Robbers, Baron). And this is what libertarians and neo-cons don't understand. The best bit of the game is the middle bit, where everyone is the most engaged, and there is real space for eventual winners to move up.
It took us till the 20th century to figure out is how to make real life Monopoly keep on working. You need a government that progressively skims people's wealth as they get richer, and which takes a fat cut out of what they pass to their kids. Obviously you don't take everyone to zero, but the trick is to keep the game in its middle stages where there are winners and losers, but people are close enough that they can move from one to the other. That's where the action is, that's where the vigor is, that's where the liveliness is.
And hey, now you can use the tax money to help people, and to invest in things like education and research that aren't profitable in the short term, but that level the playing fields in the medium term, and pay off for everyone in the long term. It's win win win win.