It's true that goods are better distributable when they are in packages. That is the common view of what Ruby gems and Rails engines are: packages for distribution. This perception misses the great value that comes from packaging without distribution. That is what makes component-based architectures: a helpful tool for organizing growing codebases. We'll talk about how to do this with (and without) Ruby on Rails.
Ruby makes it a bit hard to do packages right: you really can't hide anything. Rails doesn't want you to do it. I don't care. We'll do it anyways and it will be awesome!