You make many good points here, and the bottom line is (regarding past eras before electricity), life was often harsh and short for a lot of people. Disease and plague were major killers. Just being able to hunt or fish (or even farm under primitive conditions) probably wouldn't be enough. How many people know how to skin, butcher, and preserve the meat for long-term storage? If someone gets sick, do they have medicines, antibiotics? If someone falls and breaks a leg, do they know how to set the bone?
Are many people fit enough and strong enough to be able to handle the grueling physical tasks involved with surviving without electricity?