WordPress has become popular enough that many smaller businesses who need a (new) website and do a few minutes of research often come across it. Most of what they read tells them that it's the best platform for their website. They don't really know why, or what WordPress does, but they get it in their heads that they want a WordPress website. Not that there's anything wrong with that in and of itself.
The same thing used to happen with Flash. Clients would come to me insistent on having a Flash website, or at the very least, a Flash intro page. This one there does come with an inherent problem. Thankfully, this one has gone to the wayside.