Drupal 8 was one of the biggest releases in the platform’s history. Its release empowered the community to adopt more modern development technologies and tools. If you migrated a site from Drupal 6 or 7 to Drupal 8 you probably can attest that a considerable investment of time and resources was required for a successful migration. Luckily, migrating from Drupal 8 to 9 will likely be a walk in the park, in comparison.