Off topic threads-should be locked

[Leafless]

There have been many complaints when some members complain that there is no need to initiate a new thread on a topic, when an old one on the same topic exist.

But the point is, many of these older threads contain page after page of irrelevant information, NOT pertaining to the topic and greatly confuses members who fish through these pages to see what actually has been said relating to the original topic.

I am asking 'should it not be the moderators responsibility to lock a thread after it becomes painfully obvious, the thread is no longer entertaining the original topic matter and should be closed down'?