I think part of it is that people tend to separate things out into lots of gems. For example, if you're using Ember in your Rails app, that's two gems right the

I think part of it is that people tend to separate things out into lots of gems. For example, if you're using Ember in your Rails app, that's two gems right there just for that library. If you want to allow delegated authentication with the common providers (Facebook, Twitter, OpenID), that's like 10 gems. Your unit testing and error reporting comes from gems, your app server is a gem, every database you want to support is at least one gem, etc. It gets explosive, but it's really just an organization thing. One thing to keep in mind, though, is that not all gems are actually used at a given time. Your gems for testing, development and production all go in the Gemfile, but you're probably not going to install all of them on one system.