[Retric]

That would only be relevant if their was absolutely no other way to allocate capital and maximizing ROI was the only relevant metric. Building, a X$ Yat may count to GDP as X$ worth of healthcare, but society does not care about them equally.

What's important is the outputs of society, not the accounting that occurs between effort and consumption.

[solidsnack9000]

All people engage in consumption, though — less able people as well as more able people. The issue is, when they aren’t, what are they doing with that capital? This relates not only to how people run a business but also how they engage with civic projects, charities and institutions like schools and universities.

There are marked differences in styles of consumption. Some of the things the Romans did, for example, are simply too destructive and wasteful for our tastes today.

If you’re saying, we can allocate capital not to more or less able people, but in some other way — to institutions or something — well, that’s true; but there still will be capital managed by individuals. When talented, constructive people rise to the top of the heap and run laundromats, computer companies, and other businesses, we are ultimately all better off for it, because those services are (a) available and (b) good. But to run such businesses people do need to accumulate capital.

[Retric]

My point is there is no reason to use indirect means. If you care about efficient use of capital then add a capital tax of say 1%. Now, people who get a higher ROI accumulate wealth faster rather than those who simply conserve wealth.

When accumulation of wealth is more tightly coupled with the ability to invest rather than the ability to let compound safe investments create wealth you increase efficiency.

Beyond that I don't think capital accumulation needs any incentives. People don't invest more because of changes to the tax code they simply get more money from the same investments.