Broadly speaking, there were available on mass-produced bikes ( apart from touring or cyclo-cross setups ) 2 choices of crankset; road double with typical chainring sizes of 52/42 or 52/39, and road triple with 52/40/30.
triples were pretty essential for steep climbing, allowing the rider a low 30 ring combined with a 13-26T rear sprocket which would provide a low 31 inch gear.
Triples however are heavier and put the cranks further outboard...
A compact crankset is a relatively modern option for mass produced bikes and provide 2 rings, usually 50/34.
with a wider range rear sprocket, say 12-29T, the rider would have a 31" gear for steep climbs.
the disadvantage is you have a bigger 'drop' from one ring to the other and often drop from the big ring to the small ring then down to a smaller rear sprocket to main your cadence. Also easier to 'off' a chain!
Colnago Super, C record Delta 7v,
Olagnero Signature Model, DA 7401
Battaglin EL101 tubing 8v
Wilier Campagnolo 8v Record
Daccordi Furioso, Campag Veloce 9v