It was arguably under Muilenberg, an engineer, that many of the current issues with Boeing's culture were either created or allowed to flourish. I think it is "frequently framed" as an engineers-vs-accountants thing by engineers or others who like to think that STEM people can do no wrong.
If a customer wants to buy thousands of a widget at $1500 and you usually sell them at $2000 a widget but you can move the slider on maintainability or make an agreement that the customer accepts some reduced quality -- if that's something the two businesses can agree on and it's not a negligent change to make then it's probably worth prioritizing that. I think we might agree on that.
Trying to figure out what to do in any given business situation is usually challenging because the devil is in the details. It happens that in this particular case, Boeing should be checking that their supplier installs bolts and drills holes correctly because their supplier has screwed it up so many times. But in a lot of industries, cheaping out on materials is a reasonable thing to do if your customers agree it's a reasonable thing to do and it's not going to kill anyone.