It's a bit like Elasticsearch, I think—it's gotten big enough it won't be a quick death, but I don't see Hashi's products growing/dominating as much now as I did a couple years ago.
(As an aside, I'd like to thank Mitchell for his work over the years, Vagrant especially was huge in my infrastructure work, and Terraform was a great companion to Ansible and CloudFormation as we automated more and more stuff.)