Where have they all gone to?

I've been looking around word press,i'm following a lot of great blogs some of them have the 'blogs i follow' widget enabled so i visit those blogs as well. There are quit a few blogs that have just been left. Why i don't know. It could be because of the blog owners death. That's the only reason i can think of that would cause someone to just abandon a great blog that is well established. Some of the blogs have been up since 2008!. There was no last post saying they are done with that particular blog. It's really erie in way to read these blogs,sort of like walking into a house that has been abandoned and still has many of the owners belongings right down to the curtains on the windows. One question is dominant in my mind when i find blogs like the ones i speak of,which is WHY?why did they just leave it?. Sure,there are many books real as well as E-books  that have authors who are long dead.It just seems to me that a blog no matter the author,whether they be famous or not so famous is a very personal thing. As for my blog i can't seem to settle on a theme. I'm considering buying the custom design and maybe a premium theme for it.