Why do you think SpaceX won’t have deaths or accidents? SpaceX has had plenty of accidents and going to Mars is so much more dangerous than any space exploration ever attempted.
All launches of Mercury era rockets had non-crewed test flights of the spacecraft. And they were on proven boosters. One benefit of using ICBMs is they start out autonomous.
Both launch vehicles for Gemini (Atlas and Titan) were again completely autonomous because they were ICBMs. They were tested and proven before astronauts flew them.
The first Saturn V launch was not crewed.
As I understand all US spacecraft were largely autonomous, especially in the boost phase.
SpaceX has refined that to automate docking but it’s not new.