Great article. You don’t necessarily need certain pieces, the philosophy can adapt to the pieces that you have.
McVay runs almost exclusively 11 personnel. McDaniel uses 21 personnel but assembled a track team. Shanahan uses 12/21 in his own way as described in the article, and other coaches listed have their own offshoots, like Zac Taylor’s Bengals living in shotgun.
I posted an article during the season about evaluating OC’s, and that article mentioned that Shanahan had significantly reduced his use of play action because they stopped getting the right looks. I like that this article also laid out that it’s not about play action for the sake of play action or motion for the sake of motion, it’s more about taking advantage of how the defense adjusts to formation/personnel/shifts/etc. that was the basis of the wide zone/keeper pairing, and maybe they’ve reached the point where the look favors sticking to the run VS keeper as defenses adjust to not get burned by the PA keeper pass.