up until 1974 or maybe beyond.

I raced the Bouquet Canyon road race as a junior, 42 mi lap, a good section dirt, that year it rained, darn near a cyclocross race. I fought to the front before the dirt, that helped, fifth in, third out.
the flat I got leaving the dirt/gravel was not helpful, bike was under control but braking was useless. changing a tire in upper 30's F was no fun.
plus I was nervous about rolling a tire afterward.