Former professional Zope guy here! (I made a living building things with it in the early-mid 2000s).
What happened to Zope? Well, Chris McDonough (creator of Pyramid, and Zope veteran) blogged about this in 2011 and from my perspective he got it exactly right.
I still think this history is fascinating and I wish more people knew it.
After the history lesson, some of his "lessons learned" bullet points seem very apropos in the context of Dark, particularly the first two:
* "Most developers are very, very risk-averse. They like taking small steps, or no steps at all. You have to allow them to consume familiar technologies and allow them to disuse things that get in their way."
* "The allure of a completely integrated, monolithic system that effectively prevents the use of alternate development techniques and technologies eventually wears off. And when it does, it wears off with a vengeance."