If something were to happen to Apollo, the blast radius would be limited to those 3 people. If something happens to your car with 3 people onboard while travelling down the motorway, the blast radius could affect other cars with their people onboard. This would make the failure even more spectacular having unsuspecting civilians affected vs 3 highly trained volunteers for mission. All this to say that I think we are way underplaying "it's just a car" type of thoughts here