Because!
 

Some people don't want to deal with uber l33t players who do nothing but play the game 24/7 and spend all their money on weapons. The learning curve is also very steep for most MMOs, especially the established ones like WoW. You may be a n00b for months! Also, some people may want a more personal experience than you can get from a MMO. An RPG with a good story unfolding is like reading a good book, except it's more fun. I tend to play console RPGs more than MMORPGs for all of these reasons, and maybe more that I'm not thinking of right now.
 

LOL - I don't know HOW this second post ended up in here. Little glitch. But now I don't want to delete it on account of the comments here...

I guess having comments in the forums aren't working for everyone?