Does this happen to anyone else? As you can see, I haven’t been on this board long, and haven’t made too many posts. It seems to me that a disproportionate number end up being the last one on the thread.
Am I one of the few “total dipsticks” or do I just post to the wrong threads??

Nothing is wrong with you. Just bad luck.
But one thing that might be helpful advice is to make sure you post in the right forum when you start threads. This one really isn’t about entertainment or art and probably goes in MPSIMS.
It will probably get moved there, where you will get lots more responses.
Cheer up!
I have noticed that I seem to get the last word far too often. Of course, I’m always a day late on the hot topics. I guess I like to think that once I have spoken, there isn’t anything left worth saying! 
Somebodys gotta go back and git a shitload of dimes!
Well, we’ve been having a couple of thread-killer threads lately, and the happy conclusion we reached is that there are a lot of us self-designated thread-killers around here. You shouldn’t worry too much. When you start posting you probably tend to wait a while before putting in your 2 cents, which may well be when the discussion has died down of natural causes. Just persevere and you’ll grow bolder, and find that you can contribute too. It takes a while to get used to the way things go around here. Don’t let that bother you.
If you are still convinced that you are a natural born thread-killer, you might try your skills at one of the longer running threads. Those are very healthy and can take a blow or two. The LOTR unfortunately appears to have died out just now.
Oh, did you post to that one as the last person? Never mind.
I’d like to add that I find Bunnylady a very cute screen name.