The question is - should you bother to learn it? Learning new skills is always helpful to your career prospects and Drupal is gaining more recognition, but an experienced developer with expertise in a specific area like Java or .NET probably doesn't need Drupal skills to get a job. Large website developers and less experienced developers however, would see a lot more benefits from learning Drupal.

According to this other source and a graph of job posting matches from Indeed.com for both Drupal and Joomla show a huge climb in demand over the past two years.