cooper@ubuntu:~$ apt-cache search drupal
  dh-make-drupal - Create Debian packages from Drupal modules and themes
  drivel - Blogging client for the GNOME desktop
  drupal6 - fully-featured content management framework
  drupal6-mod-addtoany - addtoany module for Drupal 6
  drupal6-mod-cck - cck module for Drupal 6
  drupal6-mod-commentrss - commentrss modules for Drupal 6
  drupal6-mod-contemplate - contemplate module for Drupal 6
  drupal6-mod-filefield - filefield module for Drupal 6
  drupal6-mod-i18n - i18n module for Drupal 6
  drupal6-mod-imageapi - imageapi module for Drupal 6
  drupal6-mod-imagecache - imagecache module for Drupal 6
  drupal6-mod-imagecache-actions - imagecache_actions module for Drupal 6
  drupal6-mod-imagefield - imagefield module for Drupal 6
  drupal6-mod-imagefield-assist - imagefield_assist module for Drupal 6
  drupal6-mod-inline - inline module for Drupal 6
  drupal6-mod-ldap-integration - ldap_integration module for Drupal 6
  drupal6-mod-lightbox2 - lightbox2 module for Drupal 6
  drupal6-mod-masquerade - masquerade module for Drupal 6
  drupal6-mod-openid-provider - openid_provider modules for Drupal 6
  drupal6-mod-pingback - pingback modules for Drupal 6
  drupal6-mod-site-verify - site_verify module for Drupal 6
  drupal6-mod-tagadelic - tagadelic module for Drupal 6
  drupal6-mod-trackback - trackback module for Drupal 6
  drupal6-mod-views - views modules for Drupal 6
  drupal6-mod-views-charts - views_charts modules for Drupal 6
  drupal6-mod-views-groupby - views_groupby modules for Drupal 6
  drupal6-mod-xmlsitemap - xmlsitemap module for Drupal 6
  drupal6-mod-xrds-simple - xrds_simple modules for Drupal 6
  drupal6-thm-arthemia - arthemia theme for Drupal 6
  drupal6-trans-ru - Russian translation for Drupal 6
  drush - command line shell and Unix scripting interface for Drupal

This is from Ubuntu 11.10. In Fedora 16 they have a drupal7 package, but most of the pre-packaged modules are for drupal6.

That is not useful information. It only indicates that someone with package commit privileges decided to package Drupal 6 for Ubuntu 11.10. It doesn't mean anything about usage, developers, community, etc.

To put this into perspective, Debian once had a Webmin package in the distant past (about 10 years ago)...at a time when we had far less than a million new downloads per year (might have even been in the low hundreds of thousands). We're currently at about 3 million new downloads a year, and growing every year, and there is no Ubuntu or Fedora package for Webmin.

All you can assert based on a lack of packages in the standard OS repo is that there is a lack of packages in the standard OS repo.

Well considering that there are about 12,000 projects hosted on Drupal.org and that it has it's own packaging system this is a pretty pointless example. I've never met anyone using apt to install PHP applications. Given the ways that apt usually installs a PHP app, I'm not really surprised either.