I didn't abandon it, it was run by a different team, and we were one consumer of it. When the organization switched from Jira to GH issues the Jira was kept running for years, but nobody got the information into GH issues. Eventually the Jira was shut down, certainly by the time the company got acquired.

The team that makes the decision to change issue management systems and not to back up the data is rarely the team most affected by that decision.

Like many tools defending their moats, tools like Jira don’t make it easy to get one’s data out.

That isn't true though. It's very easy to export your data from JIRA. From your board, go to the List tab, filter the items to whatever you want, and then click ... and you can export the data in various different formats. Exporting as XML dumps everything.

You can trivially export your data from JIRA. If the parent experienced a situation where valuable information was lost because the instance was deactivated, that's not JIRA's fault.

I my case it was a different system that got bought out by (I won't say but your guess is likely correct) and the new license terms were unacceptable