I know of a company that's stuck on the datacenter edition, because they aren't allowed by some customers to store their data in the cloud. I can't imagine how much they must pay for that.

Until they finish evaluating competitors, and eventually migrate to .... something, they are completely stuck. Jira is at the heart of all of their workflows and they cannot and will not move to cloud. This was an Atlassian partner, but they got screwed over on that part as well.