It doesn’t miss that though, he mentions it right after the part I quoted from his article, that the exact graph shape you’re going to see will also depend on the performance of your measuring rig.
I did leave this side completely out of my analysis because I wanted to deal only with the concept of ideal response for slam. If you have to drag me over to the practical realm I will say we should strive to realize that ideal response not on this or that measurment rig of course, but at the eardrum – or actually as a devout Sahr-Griesinger-ian I should say at the “braindrum”. 
Neutralize your treble (and mids) according to the Sahr-Griesinger Conjecture 
, adjust the bass to taste/genre and you should be golden… wwwhenever the positional variation isn’t screwing you over too badly. 
(Griesinger says it worked better for him with in-ears, but I notice what he’s showing in his old video are actually earbuds. It occurs to me right now this probably works better with fully sealing earbuds/TWS that have that bulbous body stopping the insertion at the same-ish depth every time? This should reduce positional variation to the lowest that is possible in any ear-mounted transducer model, no? Hmm… and here I was treating my TWS as the ‘ugly duckling’ of my menagerie, I may have to reconsider that.)