"Test high cost against the limit of scale Musk described a concrete diagnostic for whether something is expensive because of low volume or because of a fundamental design flaw: 'What if our volume was a million units a year — is it still expensive?' If the answer is yes, economies of scale are not your problem and you must redesign. 'If it's still expensive at a million units a year then volume is not the reason why your thing is expensive — there's something fundamental about design.' This single thought experiment can instantly redirect engineering or business effort toward the right lever. Source: Elon Musk, Lex Fridman Podcast, Elon Musk"