This is so wrong on so many levels that I've lost my ability to even.
First up, as an EM resident you'll work a pretty consistent 60 hours per week on your EM weeks, and 65-80 on your non-EM weeks. You need to work those extra hours to see things- if you were only there 8 hours a day, you'd only see either the beginning or end of many of the more challenging admits. You wouldn't get to see the full arc of care, and you'd come out as a pretty awful physician because of it. Medicine isn't about reading a bunch of books and learning a bunch of things in labs- it's about learning by doing. Less time in the hospital equals less skill as a physician, worse care for your patients, and a higher chance you'll get the living hell sued out of you.
Anyone can work at IHOP. You need another waitress, you just throw up a sign, train her in a week, and you're good to go. Physicians take 11-15 years and damn near a million dollars each to train. You can't just crank them out as needed. The next problem is, when you become a physician, you are taking on a career that has a certain responsibility attached to it. You can't just ethically say, "let's all stop working over 40 hours a week and let a bunch of people die and that will show the public how much they need us!" We're better than that. Next up, if you were only working 40 hours a week, wages, in most fields, would drop substantially. A large part of the reason physicians are compensated as highly as they are is because we do work so hard, train so hard, and put in so much time. You work half as much, you're going to get paid half as much. Since the vast majority of us would prefer to be making a decent salary, and you're probably going to be working for other physicians, you have to play by the established rules of the field. You become a senior attending that makes the schedule and only wants to work 40 hours? Go right ahead, but don't be surprised if your group tries to get rid of you for not pulling your weight.
The other thing you're not looking at is that we have competition now- if we decide to act like less than physicians by working nursing hours and expecting nursing levels of responsibility, they'll just swap us out for nurse practitioners. A large part of what sets physicians apart is their extensive training and the long hours we put in to provide continuity of care. Which brings up a last point- more handoffs have been proven to cause more errors and patient deaths. It is straight up bad for patient care to have more providers caring for patients, and saving patients, not your personal comfort, is what medicine is all about.
