Apple should add many QA steps filtering out the vast majority of bad parts. First there would be incoming QA on any received shipments. And any well run assembly line contains many check steps to make sure the unit has good constituent parts. This way you don't burn good parts farther down the line on a unit that was never going to pass. Then there is out going inspection and burn in testing.
All that testing increases overall quality and value.
In theory that's possible true but in practice on an iPhone I highly doubt a DIY can do "the exact same thing". For one there are important ports we can't access, like JTAG testing the SOC. And there is a whole other factory OS which we have no idea what it does and why.
Apple should add many QA steps filtering out the vast majority of bad parts. First there would be incoming QA on any received shipments. And any well run assembly line contains many check steps to make sure the unit has good constituent parts. This way you don't burn good parts farther down the line on a unit that was never going to pass. Then there is out going inspection and burn in testing.
All that testing increases overall quality and value.