I don't think you understand quality control and manufacturing.
The same manufacturer, part, factory, assembly line and machine have variations when mass producing.
The same machine, during the day, might start in the morning with a part that only deviates 0.05% from the manufacturer specs and by the end of the day, after it gets warm, after material passes through it, after it moves, the same part from the same machine will have lower quality - meaning that the shape might be slightly off - one again, note that we are talking extremely minimum differences.
At the end of the assembly line there should be a quality control guy that will check the batches and measure to make sure that the machine doesn't need adjusting and will also mark the parts as per the quality rating.
If something is completely off, of course it is rejected and doesn't leave the factory.
But if the deviation from the norm is minimal, it might still be "good enough" for a certain brand (Seat/Skoda) but not for Audi or VW.
I cannot believe this concept is so hard to understand, but this is the last time I try to explain it... Honestly, these are very minimal variations and might only make a difference after many years of usage of a car.
Either way, we have come to mostly agree on everything related to the OP on this thread, so... I give up trying to explain this quality control variation concept

It is my field of work and I sometimes assume everyone knows what I am talking about