> Graham is arguing against an enormous straw man.This is a very hard case to make when Graham's money quote, at the start of the essay, is from a Nobel-Prize-winning economist saying, pretty much in so many words, that rich people get rich by taking stuff from poor people--which is exactly the claim Graham is arguing against.
> Nobody is suggesting that we “prevent people from getting rich” or “end all economic inequality”.
I think you're missing Graham's point. His point is not that people explicitly suggest these things, but that the discussion is framed so that they are implicit assumptions, so far in the background that nobody even thinks to question them. Judging countries by their Gini coefficient, and the criticism the US has gotten because its Gini coefficient is too high, is an obvious example. Everybody argues over what Gini coefficient is "too high" and requires action to correct; nobody even asks whether the Gini coefficient is the right thing to judge by.
> institute an unconditional basic income as an alternative to means-tested welfare programs
A key argument for which is that unconditional basic income would do better at reducing income inequality than means-tested welfare programs.
> allow every citizen/resident into a single-payer healthcare system
This I agree is pretty much irrelevant to reducing income inequality; it is aimed more at reducing the impact of income inequality on access to health care, without doing anything about the inequality itself.
> go back to the tax structure of the 1950s–70s
A key argument for which is reducing income inequality by taxing more of what rich people make. The point being that none of these measures ask why certain people have more income, which is a key piece of information. Graham's point is that if one person makes more than another because they're more productive, you don't want to "fix" that, because it's not a problem, it's what fuels economic growth. It's true that there are other ways for people to make more than others, which are not based on wealth creation, and Graham explicitly says he wants those to be shut down. But after you've shut them all down, you won't have "fixed" the "problem" of income inequality, because people's productivity will still vary, and the more technology advances, the more the variation will be amplified, so the more unequal incomes will be.