Ask HN: Why isn't rspec the default in Rails 5?

I'm personally of the opinion that rspec[0] is the greatest thing to happen to unit tests since the Test Anything Protocol. I'd like to know: why doesn't `rails new <path>` default to using `rspec-rails`[1]? Why isn't `factory_girl_rails`[2] already there? How about `database_cleaner`[3], `rails-controller-testing`[4] and `shoulda-matchers`[5]? [0] http://rspec.info/ [1] https://github.com/rspec/rspec-rails [2] https://github.com/thoughtbot/factory_girl_rails [3] https://github.com/DatabaseCleaner/database_cleaner [4] https://github.com/rails/rails-controller-testing [5] https://github.com/thoughtbot/shoulda-matchers