Drupal 8 has been out for four years now - in 2014 we were planning a migration from D6 and directly to D8. Lots of modules were missing then - and still missing now, in the summer of 2018.
The two most missed modules for us are Feeds and Rules. For two years we have been contributing and sponsoring development of both modules, and it is painful to see lack of support from large Drupal shops and how few developers working on their own time are trying to get done these large projects that any site builder needs.
So I started to read what other people are writing about Drupal 8 adoption with the goal what we can do increase this adoption rate.
From Aquia two years ago - still seems to be at the same place