The usual OSR response to the very, very, very tired criticism that old-school play was never a monolith and has always encompassed a diversity of play styles — best articulated by a widely-shared 2009 K&K Alehouse post by T. Foster
that the author of the article in the OP also links to in Part V of the essay — basically boils down to, "Yes, we know
. We already know that. We don't care; it's beside the point."
Defining a specific 'old-school' play style, even if it's pure revisionism, all but necessitates drawing hard distinctions between the way, as best as we can reconstruct, that D&D's creators originally intended the game to be played
(even if that changed almost immediately once the game was in the hands of the public; even if those selfsame creators changed their own minds a few years down the road) and the way the game actually evolved
during the real course of the hobby's history. The revision is
the point. The alternate-history, possible-path what-if-ery is the point
. The only way to get
that is to close off the avenues that the history of the game has already treaded (because they are what led D&D from old-school to traditional to modern gameplay).
That, even at the risk of being a bunch of un-inclusive meanie-pantses who dare to imagine that a very specific play-style might have an actual definition to it.