I’ve successfully done exactly what is described. You have to actually implement discipline yes. That’s the key hard part.
However provided you stick to the discipline, it’s robust e2e TDD’d versioned worked through CI and in production
You get out of all these tools what you put in
Any non-trivial project done at scale for any realistic duration won't work with this procedure.
Just consider this for a minute. If re-writes were so trivial, we would be re-writing software all of the time, even before LLMs. It is the fear of losing all the legacy additions that stop us from doing it.