what you can't really teach is the innate footwork and body positioning that makes really monster post players.
You think people are born with innate post play? That is absurd. His footwork is a direct copy of the Dream Shake. Do you know that colleges like Kansas or even smaller colleges will have a dedicated big man coach that work on this stuff? Good high school programs even have this going for them.
Moses Malone tutored Hakeem on footwork and postplay. Guy Lewis was his college coach. Foreigners sometimes have an advantage at footwork. Guys like Duncan got Hakeem get this coordination playing soccer something we do not do here in the USA provided you can play one of the big three sports i.e. Football, Basketball and Baseball.
Embiid played Soccer and Volleyball growing up. There is no innate footwork. It's all learned. Physical talent is innate but can be enhanced with weights to some degree with speed less so. Foot work is a skill, while it is true some people have better balance and athletic base, no one comes out of the womb doing reverse pivot or posting up.
How do you explain that people with vastly different athletic abilities and builds have different post up ability? McHale was skinny with low arms. LeBron is built like a tank. Bird was slow and smart. Sully is slow and has a big butt. Kareem had the sky hook. Yet all these players developed different ways to succeed at their game. Do you think Kareem plopped out with the ability to shoot the sky hook?