I feel like "capital gains" occupy a strange middle-ground between income and wealth. Capital gains clearly represent a change in your wealth, and are somewhat

I feel like "capital gains" occupy a strange middle-ground between income and wealth. Capital gains clearly represent a change in your wealth, and are somewhat "income-like". But they also are a persistent thing that you are in control of until the time of sale, and are somewhat "property-like". It seems plausible that we could come up with a reasonable-scheme for capital gains taxes that manages to accommodate both properties, but I think it'd take a fair amount of consideration to make sure that there aren't nasty edge cases, and the benefits outweigh the additional accounting.