Why Do Blogs Stop?

So, I know that blogging about blogging is the most boring thing I can do, but since my audience is small or maybe non-existent (I sort of feel a bit like Russell Crowe in "The Beautiful Mind" talking/writing to people who really aren't there) I'm taking some liberties here and expressing my wonderings.  I sometimes browse through blogs or happen upon them when searching for something and am surprised to find so many that just seem to end many years ago.  People were writing regularly and then just stop.  What is written is still interesting to read but the ending is abrupt. It's like watching a movie and having the DVD freeze up in the middle.  Or reading a book and losing it somewhere before you finish.  It always causes me to wonder why the person stopped.  Did life just get too busy?  Did they become ill or have some tragedy befall them?  One woman was blogging in January about a flood near her house and then another post in April and then....nothing.  A few are blogs that I try to follow because they write about common interests.  Are they no longer interested in these interests? And, I also wonder, just how long will blogspot keep an inactive blog online?  In any case it doesn't seem like a conscious decision to stop blogging.  It seems more like it "just happened".  I miss the "closure", but I suppose that's my issue.  I AM one of those people who likes to watch a movie from the first frame to the last without leaving for more popcorm or a trip to the rest room.  Hopefully when I stop blogging it will be with purpose and with a heartfelt farewell to my audience....real and/or imagined.