I think there is a fundamental difference between a opensource appstore and the iphone app store in terms of competitors for a particular app. If a plugin is open source how do you stop people cutting and pasting the code and claiming its theirs - or simply shortcutting by reading the source code and rewriting - so an open source app store is not the same as a everyone for themselves fight it out iphone app store. Its closer to a drupal plugins site - where multiple maintainers - add features to a code base - and there is big difference between the best plugin for a task and a random plugin that a developer uploaded at the end of a project.