> They coincided with a long period of much more effective broad-based growth and less concentration of wealth at the top
And the latter was a side effect of the former; the attempts of the rich to concentrate wealth couldn't keep up with the broad-based growth. But it wasn't high marginal tax rates that allowed everyone else to reap the benefits of that broad-based growth; it was the fact that the growth was outstripping the concentration of wealth. Most of the revenue that went to the government from those high taxes didn't get redistributed to the people at the bottom; it got spent on things like the Korean and Vietnam War (and more generally the Cold War military-industrial complex), subsidies to large corporations, etc. Even Social Security and Medicare, the two poster child programs for the government redistributing wealth from the rich, don't actually do that, because your benefits are based on how much you pay into the system. (Not to mention that the government has raided the trust fund that was supposed to fund those programs for decades, so the fund now has government IOUs in it instead of cash, and those IOUs have to be paid when they come due from current revenues, not from earnings from prior payments in. It isn't the rich that are going to have to pay those IOUs.)
> that wouldn't in and of itself be more than very weak evidence that we couldn't do better through government.
Governments have existed for millennia. There is a lot more evidence about how badly governments do things than just the US in the few decades following WW II.
And the latter was a side effect of the former; the attempts of the rich to concentrate wealth couldn't keep up with the broad-based growth. But it wasn't high marginal tax rates that allowed everyone else to reap the benefits of that broad-based growth; it was the fact that the growth was outstripping the concentration of wealth. Most of the revenue that went to the government from those high taxes didn't get redistributed to the people at the bottom; it got spent on things like the Korean and Vietnam War (and more generally the Cold War military-industrial complex), subsidies to large corporations, etc. Even Social Security and Medicare, the two poster child programs for the government redistributing wealth from the rich, don't actually do that, because your benefits are based on how much you pay into the system. (Not to mention that the government has raided the trust fund that was supposed to fund those programs for decades, so the fund now has government IOUs in it instead of cash, and those IOUs have to be paid when they come due from current revenues, not from earnings from prior payments in. It isn't the rich that are going to have to pay those IOUs.)
> that wouldn't in and of itself be more than very weak evidence that we couldn't do better through government.
Governments have existed for millennia. There is a lot more evidence about how badly governments do things than just the US in the few decades following WW II.