One of the key reasons that Drupal has been successful is because we always made big, forward-looking changes. As a result, Drupal is one of very few CMSes that has stayed relevant for 15+ years. The downside is that with every major release of Drupal, we've gone through a lot of pain adjusting to these changes. The learning curve and difficult upgrade path from one major version of Drupal to the next (e.g. from Drupal 7 to Drupal 8) has also held back Drupal's momentum. In an ideal world, we'd be able to innovate fast yet provide a smooth learning curve and upgrade path from Drupal 8 to Drupal 9. We believe we've found a way to do both!