The practical answer
A prototype proves the idea. Production software must also handle real users, real data, failure, security, deployment and ongoing change.
Questions teams ask
What usually changes first?+
Architecture, authentication, data handling, error management, testing and deployment are common areas that need strengthening.
Can the prototype code be reused?+
Sometimes. The right approach is to assess what is useful, keep what is sound and replace the fragile parts rather than rewriting automatically.