Reminds me of this article by Li Hongyi: https://www.csc.gov.sg/articles/how-to-build-good-software

Quotes:

"The main value in software is not the code produced, but the knowledge accumulated by the people who produced it."

"This is why relying on external vendors for your core software development is difficult. You may get a running system and its code, but the invaluable knowledge of how it is built and what design choices were made leaves your organisation."