I think you have that backwards. Gatekeeping (certain) drugs requires expert clinical knowledge to achieve the right results without harming the patient. This is one of the primary focus areas for physician training.
If patients need lifestyle advice then going to a highly paid physician is a waste. Those patients should start with a (cheaper) therapist, personal trainer, dietician, or social worker. We can't reasonably put the entire burden on physicians; it's too much for one profession to handle.
If you go to those people and tell them you have pain and you need to know which muscles to strengthen and which muscles to stretch, whether to rest or work out or get an x-ray, etc. they tell you to go to a physical therapist. But you need a referral for a physical therapist, so you have to go to a primary care physician first. All they do is throw drugs at you so you basically have to lie about taking the drugs because no I don't need painkillers I need answers, and then you can finally get your referral and go to the physical therapist who can help.
I've had this experience once and my wife has had it thrice (different doctors, different injuries).
By asking primary care physicians to gatekeep drugs, we're introducing a bias where when you walk in the door they assume you're after drugs. I don't have a solution for how best to gatekeep drugs, I just wish I could find a doctor who was unencumbered by that task so they could focus on healthcare instead.
You don't need a referral to visit a physical therapist. You can just make an appointment and go.
Certain health insurance plans may require a referral in order be reimbursed but that's not universal.
if this were true, why do the pharmacy rules vary considerably among different countries. In the US the rules are very strict. In Europe moderate and in Mexico very lenient.
Every time you try to change a medical policy the threat is "you'll kill grandma". the fact is that grandma's care is awful and we need radical changes.