It has been years. I’ve been able to edit posts from at least July 28, 2014 prior to whatever change was made about a week ago. So I’m not sure why you would say it’s never been years.
This post is more than two years old and I made an edit on it on July 9 of this year.
While I haven’t edited this post since January 8, it was still more than two years ago from the initial post.
And there is this from the Hey, how can I get Discourse to do X? thread from July 2 of last year:
That’s from post #15 of the thread.