You're absolutely right, but after so much success there also seems to be a fair amount of confidence/arrogance that set in at NASA regardless of other pressure

You're absolutely right, but after so much success there also seems to be a fair amount of confidence/arrogance that set in at NASA regardless of other pressures. Additionally, when you have a civilian on board, I think it really changes how you think about what an appropriate level of risk is (13% might have been ok with professional astronauts who knew the risks beforehand, but likely was too high for a civilian). And the line engineers at Morton Thiokol fought back pretty hard on the decision, even if it might have impacted their careers negatively.