You're far far of the mark.
I work in engineering in exactly the kind of situation you're expounding on. My company makes many thousands of any particular model.
It is in fact not especially difficult to make changes within any particular product to cheapen it.
30 years of my life are invested in product design and development. Don't hand me that line of crap. It is in fact extremely easy to make changes and substitutions that result in real cost savings for the manufacturer without inordinate expense to do so.