Push starting cars was relatively common back in the day compared to today. In my view, the main reason was the cars then had generators and not alternators. A generator as you all know does not charge much at idle as compared to an alternator.
Then you have to consider that with a 6-volt, system you have to supply twice the current to get the same wattage as with a 12-volt system for lights, radio, heater fan, etc. I also recall that few car owners had their own battery chargers, possibly because the money was used for other more important things. Today there are many inexpensive battery chargers available. The starter motors on newer cars draw less current than on the older starter motors without permanent field magnets. Nowadays the cars use more and more LED lamps that use much less current for the same light output and I suppose that battery technology has improved over the years as well.
Today the 3EH batteries I buy from Tractor Supply for my 53 Special are better than the original Delco OEM batteries available back in the day.
Push starting cars also ended when automatic transmissions were built without a rear pump that was driven off the drive shaft. Your pusher car driver got the stalled car up to 25-30 MPH, hit his brakes and blew his horn and the driver in the car being push started put the transmission into Low or Drive and hoped it would start the engine.
Brings back memories!
Joe BCA 33493