Yes, I understand Saez disagrees. But he is hardly the final word on this. Hardly.
In some cases. Investing in the stock market doesn't. It's just a somewhat randomized wealth redistribution system. If I invest $1M in IBM, IBM doesn't see any of that money. Nor do the investors in IBM. It might move the price of a fraction of a penny, but the money just goes to whatever person sold their stock.
So, some investment (private companies, municipal bonds, etc) leads to more economic activity, but not all investment. I'd be interested to see the breakdown.
most 65 year olds who are wealthy at 65, weren't at 30. Just pointing out that if you support a policy because you don't think it will affect you, it very well might later on. But that's an aside point, not the main point.
You don't seem to want to understand my point: Low taxes for investment benefits wealthy people disproportionately. Yes, lower income also get some benefit but the vast majority goes to the wealthy. Same for all the Republic "tax reform" proposals: A little tax cut for small incomes, large tax cut for high incomes.