People that have done QA have the best understand of this.

I was doing the QA on a life safety product. Any new hardware would mean pulling the specs for the ICs and verifying that the layout and pin-out where correct on the product designs. You don't need an electrical engineering degree to know that PIN-1 on IC-2 should be connected to PIN-A on IC-4 but deigns having it traced to PIN-C.

Not once was there ever a recall and all early product issues where just a firmware update. After no longer working at the company they stopped doing QA. Heard from a former coworker that they latest product releases have required a compete recall.

QA not only saves lives it also reduces service and support costs. It helps keep a good standing relationship with your clients. Good QA is about trying to brake the solution as a consumer not reading the manual.