I think Grunf and some others are overlooking the fact that Boeing and Airbus (& Bombardier & Embraer & BAE etc.) are in intense competition with each other - and none can allow their safety reputation to be seriously compromised.
The engineering process in aircraft & systems design is either to make an item prime reliable (wing spar, turbine disc, etc.), or else incorporate fail-safe features that will stop or mitigate a failure long enough to be detected and mended. The media, and the lawyers listening to the whistleblowers, cannot comprehend the implications (or lack thereof) of the failings of an OEM; all they can see is "safe" or "unsafe". (Give me a break!)
Is any other engineering discipline required to meet such criteria under the commercial constraints of minimum weight, very high unit performance, economical operation etc?
And in a successful design such as a Boeing or Airbus, so many units are built and sold to so many customers, that secrets don't remain secret very long. Pprune is ample evidence of this.