Try learning to vibe code on something totally greenfield without looking at the code and see if it changes your mind. Ignore code quality, “does it work” and “am i happy with the app” are the only metrics.

Code quality is an issue you need to ignore with vibe coding - if code quality is important to your project or you then it’s not an issue. But if you abandon this concept and build things small enough or modular enough then speed gains await!

IMO codebases can be architected for LLMs to work better in them, but this is harder in brownfield apps.