1) There are certain issues which are unlikely to receive spending due to well-known economic effects. For example: building highways and public transportation

1) There are certain issues which are unlikely to receive spending due to well-known economic effects. For example: building highways and public transportation are things unlikely to be funded by individuals because they are public goods. 2) There is little evidence that the high tax rates in the middle of the century led to decreased productivity. Tax rates are marginal, meaning that more effort leads to more reward, still. Lastly inequality as it grows more extreme is a problem in and of itself. Unless you posit that the effort put in by the top 1% has increased a lot, then what we have is a situation that seems unfair. And this is demotivating, and will lead to instability in society even more than it already has. Why would you try to push forward your society if it seems like no matter what you do, wealth inequality is just going to increase, and the top 1% are going to capture most of the rewards? It's true that it's a rising tide that floats all boats, but if some are being floated much more than others then there are issues around power that are concerning. We already see evidence that increasingly the government is less responsive to those without wealth and more responsive to those with wealth. Wealth may be a zero sum game, but power is not. If we allow wealth to concentrate, then power concentrates.