Yes, that does happen too. But the most recent examples I mentioned of old threads being closed were about Christmas gifts (not relevant right now, inactive since January); people trying to decide what college to choose…in 2020; someone asking about a particular program, another two year old inactive thread; and so on… Someone recently revived the cake vs cupcake thread. It gained traction and is open. (Btw, We only knew about the thread because it was flagged due to having been inactive.)
If you stumble on an old thread and post on it, only to find it then gets closed, I suggest first checking to see how old it is. Generally, we close old threads because very often the person who posted is long gone. Maybe they were a high schooler and are now a junior in college who hasn’t been on CC since 2019. Unless the topic is general enough to be relevant to a lot of people, there isn’t a lot of point in keeping it open. The OP won’t be returning to respond. Maybe the information in the post is now outdated or irrelevant. So our standard practice is to close old threads.
BUT, if you find a thread has been closed and you’d like to keep it open, you can flag it. We review ALL flags. You can click the Something Else option and state why you’re flagging. We have reopened old threads before. We are real people, not bots.
P.S. Yes, I myself have created a lot of split threads to form new topics. I did this recently, but the person who posted didn’t want it to seem as though they had started a new thread, so they deleted their post. Oh well, I tried.