While this is true, some parts are so simple and have been designed/updated with so much experience and feedback, the defect can only be because of Quality control or Bad design.

Like if shopping around get them the material that is so cheap it is not the same, if the parts weren’t treated or finished like designed, if the tolerances are the issue or some other problems you would think should not be an after decades of engineering in engines.

I would appreciate more infos on if manufacturers have something like design rules that would say any rod bearing for cranks of X diameter,x oil grade made to spin to x RPM and up to X operating temperature needs to have X fitment and X metal treatment to avoid this issue.