Matt already addressed this in another response. If you you work to maintain investments, the income is mixed, but part of that income is a return produced by the work that the capital is doing, not the person.
I would point out to those who claim that returns on capital are a “risk reward”, owners of capital merely risk losing their investment. Workers, whose labor income is far less than the risk reward of capital, risk their life and limb logging, working on oil platforms, etc. The relative market values of the risks do not seem justifiable.
This is because income is not a “reward” at all. It’s just the marginal utility of your input, whether labor or capital. Whether the income is justified is a moral or political question, not some fact of nature. Who gets how much income for what is a social decision we make.