That article has too many flaws to go into... Such a cute - yet content-free - dismissal. It's also pretty clear from your "critique" that you didn't even read

That article has too many flaws to go into... Such a cute - yet content-free - dismissal. It's also pretty clear from your "critique" that you didn't even read the article - while Sumner's examples do use a positive rate of return, his argument is independent of it.