Even if it's a small percentage of providers and nurses it doesn't change the number of deaths per year from those errors. When I'm in the pharmacy picking up my deliveries I regularly hear a pharmacist on the phone with a doctor explaining to the doctor that the drugs he's prescribed are contraindicated in the combination he prescribed. So thankfully a smart pharmacist is preventing some medical errors that could have had a negative outcome.
I've lived it for 30 years. There are doctors practicing that I wouldn't let pop a pimp on my ass. Trying to watch a doctors reconsile patients medication on discharge is scary. Back when I was in the Navy, my supervising physician diagnosed a patient with a lipoma on his neck. I saw the guy a few days later and it wasn't a lipoma, it was a lymph node, and he had one on his chest and underarm, loss of weight, loss of appetite, night sweats, elevated wbc's with a left shift. An intern should have known the kid had Hodgkins lymphoma. I went to him to let him know I was sending the kid to get a CT and he then said it was a super infection, lol, and ordered me not to send him for a CT. This was the senior squadron physician. I ignored him, saved the kids life and was given a letter of reprimand for insubordination and disobeying an order. Every serious misdiagnosis I saw during that tour was that one doctor. TOTALLY worth it.
Imagine how many bad doctors there'd be without regulation.
I once worked with a surgeon that was so bad, he couldn't get malpractice insurance anymore, so he joined the navy, and because of his years of "experience" he entered service as a full bird captain. When he killed or maimed too many patients in the Navy, they freaking promoted him to the director of surgery, to keep him from seeing patients.
It's always a few really, really bad physicians killing patients in each system.