Hello. I am here. Discourse doesn’t give us the ability to close old threads en masse, and it’s a feature, not a bug: when it was designed this was a specific choice. I see what you’re saying about obsolescence of the information, but I think in many instances we’ve had conversations that have been had in the past…but they are in new threads. I could go on at greater length, but there’s no sense in arguing the point because we can’t batch-close threads.
As for OPs having left the building…I don’t know if you’ve noticed, but there were situations where these old threads’ OPs have come back because our system sends a notification of a new post. The n is now large enough in this sample size that I am not surprised when people come back to respond…even years later.