Should the Semicolon follow the diastole, the trigon, the interpunct, and the diple?

…Thus readeth Johnson's Economist column on how punctuation is being changed by computers and the internet.

Most people take punctuation to be something obvious and settled.

… The first English writers, when they punctuated at all, availed themselves of long-forgotten symbols like the diastole and trigon, the interpunct and the diple. Printing began the process of settling the punctuation system, but even that took four centuries. Samuel Johnson’s commas, in the mid-18th century, were not only heavy; many would be ungrammatical today, and this style persisted into the first editions of The Economist in 1843.…