With Drupal 9 set to be released later next year, upgrading to Drupal 8 may seem like a lost cause. However, beyond the fact that Drupal 8 is superior to its predecessors, it will also make the inevitable upgrade to Drupal 9, and future releases, much easier.
Acquia puts it best in this eBook, where they cover common hangups that may prevent migration to Drupal 8 and the numerous reasons to push past them.
The Benefits of Drupal 8
To put it plainly, Drupal 8 is better. Upon its release, the upgrade shifted the way Drupal operates and has only improved through subsequent patches and iterations, most recently with the release of Drupal 8.8.0.
Some new features of Drupal 8 that surpass those of Drupal 7 include improved page building tools and content authoring, multilingual support, and the inclusion of JSON:API as part of Drupal core. We discussed some of these additions in a previous blog post.
Remaining on Drupal 7 means hanging on to a less capable CMS. Drupal 8 is simply more secure with better features.
What Does Any of This Have to Do With Drupal 9?
With an anticipated release date of June 3, 2020, Drupal 9 will see the CMS pivot to an iterative release model, moving away from the incremental releases that have made upgrading necessary in the past. That means that migrating to Drupal 8 is the last major migration Drupal sites will have to undertake. As Acquia points out, one might think “Why can’t I just wait to upgrade to Drupal 9?”