[bluGill]

>But if a car manufacturer consistently uses a production methodology which causes door handles to keep falling off, again and again, even after they've been re-glued on for the Nth time...

We know the characteristics of glue, and have switched to better glues. All our assembly jigs work with glue. When the handle falls off it is easy and cheap to glue it back on.

If we switch to screws we need to redesign the parts and the jigs; and reorder the entry assembly line. [Not realized by the engineers at the time is if they use screws dissimilar metals of the screws corrode and result in the handle falling off as well - and it is a much more expensive fix because you have to replace the handle and the part it attaches to as both have nothing to screw into)