People will from time to time revive long dead threads. I once did it by accident. I was checking out a provider, and she had links to reviews. I just didn't think to check if the thread was on old thread, so, I posted in the thread and someone complained I revived a dead thread. And, they were right, I did. I didn't mean to, I just didn't think to check.
Of course, mods could override that on specific threads if they deem a reason to.