[MichaelZuo]

Yes it does when there are several stages of prototypes and engineering builds before the actual production vehicle is shipped to customers... and the hundreds of other mechanisms and systems that major automakers use nowadays. I mentioned QC because it's the first screening for arriving parts, not the only thing that occurs.

Do you not know how car manufacturing works?

Anyways you don't have to take the quality of RR parts on my word if you still think it's impossible, just go a showroom and inspect it yourself.

[YouWhy]

Design iteration is typically a long tail phenomenon - new issues keep coming up as the system (car) faces new scenarios.

Even a high-resource prototyping program can only go so far with scenarios like - wear and tear/part fatigue, adverse environmental conditions, local peculiarities (e.g. regulatory requirements for uncommon configurations), unintended but common maintenance mistakes etc.

For example, a Fiat car my family owned suffered a cascade drivetrain failure after about 9 years on the road. I don't think a prototyping program could have captured that ahead of time.

The fact that the showroom RR parts look fine only indicates that the parts are ok immediately after manufacturing; it does not promise they'll work fine after several years even if treated will.

[MichaelZuo]

> Design iteration is typically a long tail phenomenon - new issues keep coming up as the system (car) faces new scenarios. Even a high-resource prototyping program can only go so far with scenarios like - wear and tear/part fatigue, adverse environmental conditions, local peculiarities (e.g. regulatory requirements for uncommon configurations), unintended but common maintenance mistakes etc.

Which is why automakers typically recommends a maintenance schedule that catches the vast majority of potential failures before they occur on the road.

How does this, or anecdotes of your family's Fiat, relate to engineering and verification practices of parts coming in from suppliers?