Re: Automotive qualified parts take a long to time
"If new_part_cost <= (old_part_cost - 50p) then bite supplier's arm off."
No!
I used to have a steel industry customer which made very, very basic parts for a motor manufacturer. When they had quality problems, their customer didn't replace them - qualifying a new supplier for even these basic parts (which you could make in your shed) would have taken a year or so. Instead, they sent a team to the supplier to help them iron out their quality issues.
True, the automotive industry is very price sensitive, quality and reliability of supply are just as important.