If you're hammering the SoC you usually have a socket close to you.I think it depends on the tasks a user uses their laptop for. If someone is hammering the SoC, then battery life really isn't anything like as good as it otherwise would be.
Don't get me wrong, of course, I'd like a week's worth of battery life in the MBP. However, it would probably be a compromise in the thickness of the device. I prefer an all-day battery life and a lighter and thinner device.