The big difference is is 4 people vs 10 and 2000 ft.lbs air hammers vs a 4 lb hammer on a slogging wrench.
Not really amazing.
Also remember in the 50's 100 mph was fast so a minute in the pits did not put you that far from the lead.
Now days 300 mph is considered fast so 1 minute has you with a 3 lap deficit which is almost impossible to overcome.
Not sure when it changed, but have you noticed the IDY cars are no longer sporting the air chassis jacks. They are now using man power, two guys front and rear with manual lifts.