A closely allied idea to "never rewrite" is "you can always refactor shit into gold." For the first ten years after reading the Refactoring book I believed the second claim was true. Don't get me wrong, I think you can make great improvements to a code base with Refactoring. But sometimes a re-design really is needed.

Eric Normand addresses one facet of this by saying "you can't refactor Aristotle to Newton": https://lispcast.com/building-composable-abstractions/