I worked at a company that bailed on a JIRA Server to Cloud migration and went for enterprise instead because cloud's performance was so poor compared to the self hosted version.
We did have people actually migrate away from JIRA because they didn't need the features, not really because they were required to move to the Cloud instance. But the fact that they now had to move at all made it easier to switch (some went to Redmine for some reason, others went to Git-SaaS integrated boards).