It can go both ways. At work, I periodically get in contact with an extremely large codebase that is actively worked on by multiple teams. One complaint I heard was that people doing willy-nilly things cause setbacks to efforts to make project-wide improvements. One example was that build times were very slow and there was an effort to implement incremental builds along some interface boundaries, but then teams would disrespect agreements to not violate constraints for that boundary (because immediate deadlines trump long term large efforts)

A more accurate way of thinking about it, IMHO, is to look at how homogeneous the project is. A project can be very very large, but be entirely CRUD forms, and Rails could fit like a glove. But on the other hand, a project could have predominantly "curveball" features (maybe it simultaneously has a real time chat component, twilio integration, newsletter emails, periodic 3rd party data imports, print-to-pdf, etc).