Any info could still be useful years later. For example, i was searching about UV lights and found an old post where people kept posting new info for many years later. As i joined late, i got to read all the info in one place, and there were lots of updates that were gathered throughout the years. It wasn't an official important post either, it was just some guy asking for help with UV and people continued sharing their experience for a long time. It was not worthy of making it a sticky, but it's still valuable.Because someone answering a post from 2010 "helping" someone solve a problem that is likely not even on the forum anymore doesn't help anyone. Waste of time and clutters up the thread list for people asking questions for current issues.
All good, just suggesting something to improve the experience on the forum as a relatively new member. If a thread has so much value, make it sticky, otherwise, let them die.