I understand the skepticism and I can't claim I am right. But some points come to mind.

First, I think we overestimate how different code is from other code. We even joke about CRUD apps and how cookie-cutter they are. A lot of changes in those apps are: add some new features to a data access layer (SQL, ORM, whatever), add new routes, add new UI surface, etc. There is an entire industry around "Design Patterns" and people live by the DRY axioms. Things like Ruby on Rails exists because rebuilding these systems over and over is wasteful. I feel we are just moving further down that same path.

Second, your question of "why would we want" is totally backwards. Progress doesn't follow your desires. Progress doesn't require justification. Sometimes we adapt the environment to our needs, other times we adapt to a changing environment. Which case we are currently in is still undecided and you are free to fight for the future you prefer. But demanding an industry justify itself before it is allowed to change fails in the face of evolution. If it works, we will justify it in hindsight.