Remember when the same comments were made about Apple’s ability to do phones, about how “they just can’t come in here and compete with phone guys?”
Yes, Musk has improvisation debt. You know what he doesn’t have? Technical debt. Union debt. Musk has the chance to create a new kind of factory and manufacturing, something existing Japanese, German, or American automakers aren’t likely to do, simply because of their existing stakeholders.
Starting from a clean slate on anything implies a messy scaling period. It’s a risk, but the potential rewards are far higher.