I bought a 1974ish Roberts bike (custom uk builder) the gearing was insane, 45-55 on the front and 13-18 on the back, I assumed he had it set up for time trials or the like but was assured that it was pretty typical for the era and the guys would just power up the hills.
I think it was a bit of bravado rather than good sense... rather like the weight obbsessed carbon freaks of today, or the fixxy obsessives.
I ended up changing the rear cassette for a 13-24 which is much better on the hills, but I only use the big chainring about 1% of the time.
I think the 'half step and granny' was common in touring bikes, but i guess that would be later when better chains came allong