Where was it proven that brand name stuff has less defects? If the companies were non-profit we'd be guaranteed the extra money was going into things like research, higher sampling QC, employee wages, etc.. - but they aren't.

It's entirely possible the entire portion of the higher price tag is being used for profit, not paying the factory to do more QC and trash more defective product without shipping it out. The factory is often even the same, like how Giant makes bikes for big brands. So the non-big brand actually has less overhead since there's one less layer of bloat to pay for (execs, managers, marketing and branding, etc.). Entirely possible cutting out the middleman also allows spending more on QC in the same way it's entirely possible a higher price tag does.

As someone who worked for a popular brand manufacturing a popular product once, I have to say, a lot of the decisions did not lead to higher quality at all. Management would make crazy decisions like force us to use a decade old, out of production, out of support Texas Instruments chip instead of some modern option, and we'd spend month after month struggling with it - all because using it improved the bottom line.