I agree that Wikipedia wasn't the best source to go for criticism: Wikipedia is very sympathetic to the claims like in the book, so the criticism section is very weak sauce.
It is indeed noble that the authors responded to the criticism, but unlike what Wikipedia seems to imply, they didn't manage to rescue their argument.
A blog post referencing another blog post doesn’t seem to rise to the level of total disregard for the original study. But maybe we can try Wikipedia again.
Good points, he seems to be in to something in the health field, but the analysis was incomplete and flawed. Given the importance of the health results, perhaps someone could build on top of that and build an improved study?
The problems of inequality go well beyond living standards. E.g. political control in a very unequal society gets concentrated in a few people.