Any confluence like tool (wiki/sharepoint) is only as good as the people who populate, edit, and curate it. The tool itself (confluence) is generally not a problem, the problem is that documents go stale and/or are badly organized. You can't really automate yourself out of that problem. Just because any given document hasn't been touched in months or years doesn't mean it's actually out of date.

I remember for about 5 seconds in late 90s early naughts there was talk of this role of 'information architect', a sort of a digital corporate librarian. I imagine such a role should still exist, but who has the headcount?