I remember reading a report by a major car manufacturer who had done a tear-down analysis of an early Tesla. This is a normal process where they take competitor vehicles apart and analyse the engineering, weights, costs, assembly processes etc.
The conclusion was that it left an awful lot to be desired regarding design for assembly, which would inevitably lead to significant variation in build quality. There were examples of "bracket on a bracket" type assemblies, too many tolerances stacking up and costly build, and likely reliability issues.
I imagine the design process has evolved and is now significantly better, well at least I'd hope so.