I also like the old threads, and am a little leary about locking them, even after 5 years. There is a wealth of valuable information in many of them, and I think many of them could continue in "real time" to add/update what's gone before.
Sure, some are outdated. But in others, previous posters have gone into great detail on things such as choosing equipment, buying boots and shoes, foot care and so on, that doesn't necessarily need to be repeated for a new member every couple of months (or weeks,lol) but could simply be continued in a single place.
Like others, I found myself a bit confused when some of the old threads started popping up. But it's been fairly easy to catch on. If there were some way to earmark a gap of, say, several years that might be helpful. Or some other alternative.
But I do think the institutional knowledge in the forum is a valuable resource that isn't found onthe Facebook, etc., sites. I hope that never changes.