I think you’re misunderstanding what most of them keep practicing. It’s not the kooky cranial/cervical manipulation(you can make an argument that them having to learn that stuff in the first place is BS and a waste of time), but most do pick up a few muscle pressure point tricks and stretches that are essentially the same as what PT instructs patients on how to do. Is it bullshit? No more so than most medicine that’s practiced(the data behind the vast majority of what your average physician does is at best all over the place, the truly “settled” clinical questions are few and far between). In my book though, anything that keeps you from having to prescribe a scheduled drug (read as:narcotic or muscle relaxer) to get someone functional from something like severe trapezius tightness or piriformus syndrome is a heck of a tool to have at your disposal in a primary care or urgent care setting.
Even phevs have this availability. Loving our Mazda cx90 for this feature. Can program their app to have it start warming 15-20 mins before my wife leaves for work and it’s ready to go and comfortable.