Board Thread:General Discussion/@comment-25413416-20140922093524/@comment-3974711-20140924141920

You missed the point.

Azmuth's intention for Primus was not just a repository of alien DNA; it was a repository of alien DNA for the Omnitrix.

That means that it would only contain DNA that Azmuth would have had collected. Whether there are other planets similar to Primus that house DNA of other galaxies is irrelevant.