From a quick Googling, the heaviest Mercury capsule launched weighed 3k lbs, while Crew Dragon is 20k lbs dry. That extra mass makes the problem significantly m

From a quick Googling, the heaviest Mercury capsule launched weighed 3k lbs, while Crew Dragon is 20k lbs dry. That extra mass makes the problem significantly more complicated. As for later programs like Apollo that are more comparable, I'm not sure. Maybe they were comfortable with heavier systems or worse safety margins. Also, I expect that working out the parachutes for Apollo was not easy.