This article only shows examples that supports its points. Most of the long email discussions happen over a period of a few hours and you don't need much contex

This article only shows examples that supports its points. Most of the long email discussions happen over a period of a few hours and you don't need much context to know what is being discussed. For these kinds of emails (which are the majority of the messages I read every day), interleaved replying is a nuisance since you find yourself having to skip over the same content over and over again. This is why top posting won this battle a long time ago (when hotmail appeared, pretty much).