Providing a barebones core and allowing contributors to build onto it is a fairly tried and true strategy (Django and Drupal are two examples that come to mind). As time goes on best-of-breed contributed modules will gain acceptance (socket.io is one that seems to have achieved this).
I wasn't talking about the nature of the technology, just the degree to which they include a "standard library". There are plenty of pluggable apps for Django and contrib modules for Drupal that are used on almost all sites, but they are not distributed with the project.
