@scottgal My take was "rewrite the stack" was hyperbole for a ju-jitsu-like "make the right set of changes to dramatically change things" rather than a literal Musk "we need a total rewrite!!!" which sounds like NIH.
Often that's still a challenging project, like a rewrite of a key component, but yeah, not an end-to-end rewrite.
(Maybe I was overly generous in my interpretation of the post. :)
@sgf Yeah I think the fancy name is 'Transformational Architecture' or less fancy 'code jenga'; changing a running app and making it better while keeping it running I think only really comes from experience. The irony is that the more able you are to manage that sort of thing the less likely you'll be in a role which allows it.