Over the past few years lots of amazing work has been done on the unofficial Drupal 8 CiviCRM release. The core team have looked at this and are now in a position to complete the work to make this an official CiviCRM release. We have also factored in time which will allow the CiviCRM core team to address any unforeseen issues which may occur. This will include installer changes and integration of Drupal Views. We've identified and are working through issues here https://lab.civicrm.org/dev/drupal/wikis/drupal8-composer
The move from Drupal 8 to Drupal 9 will not be like previous Drupal major updates. The CiviCRM core team has looked at this and the Symfony 4 code changes required should be minimal as the Symfony version change is the only major change between Drupal 8 and 9. So this work is also preparation for Drupal 9.
We promote CiviCRM as being built by nonprofits, for nonprofits, yet only 5% of project funding comes from campaigns like this one. You can also shape the direction of CiviCRM by supporting campaigns like this one. Every dollar counts!