In all fairness a visitor now, who sees random old tweets, will assume the status tweet page is unmaintained and useless.

No it won't. At least not for me, a not-logged-in user. What's an "active post" anyway? A pinned post is at the top, but what status page constantly pins and unpins their latest post?

When I go to most Twitter pages, now, I see completely random posts from years ago at the top.

That is not necessarily true. I don’t have an X account; if I go to Musk’s X page I see his pinned post followed by something from 2022. So Slack could always pin the most recent post but they’d still lose the progress of the incident.