Titanium was in use to a limited degree with Campagnolo but they were limited, expensive and prone to fatigue cracks, Teledyne had a titanium frame road bike in and around 1973 -75 for instance, Bullseye alloy pulleys became a bit of a status part though not really any lighter but the anodized red finish added some bling. Lighter tubular tires of course.
There were not really any advances then that finally became available into the 1980's and beyond to truly reduce weight without losing strength and ultimately reliability. Using the best and lightest parts and thin wall tubing a road bike back then could weigh under 20 pounds which is still quite good.