The amount of fire activity for ANY city is hard to compare with the fire activity in any city now. And not only building fires, but every other kind of fire. Car fires, rubbish fires, dumpster fires, even brush fires, everything was burning during those years. Maybe not in NYC but in other cities around, a busy engine company was doing 1,000 - 1,500 runs a year. But usually when they went out the door, they were putting water on some kind of fires.
Most didn't respond to the amount of medical calls or fire alarms as they do today. There wasn't the amount of battery operated smoke detectors like there is today. A fire could spread before somebody knew about it.
Cell phones have also changed things for reporting fires. At the first sign of a fire, most people will call it in. No more looking for a pay phone or fire box on the corner. It's pretty rare today that a fire gets a good head start.
Fire Investigations have come a long way from those 70s and 80s.
In the 70s/80s, going to just about any city, at least here in the northeast, there was a building fire. Not counting the FDNY, I could go to Newark, Boston, Bridgeport or Providence and see a fire.
Over the last three years, the busiest city for Working Fires has been New Haven in Connecticut. During that 3/4 year period, that city has the record of 77 Working Fires (10-75s or greater) for the entire state. But their War Years today are not the fires. Recently they went to a shooting where six people were shot. It's a different kind of War Years.
During one year in the mid 80s, Bridgeports (a similiar sized city) record was 751 Working Fires. Last year they had about 70 jobs.
For most places today, instead of the companies going to those trash can fires in the street, they are going to a seizure in the street. As I see it today, the FDNY isn't much different.