I'm also one of those people who own way more Go books than I "should" have.

I tend to pick up new ones when I feel "stuck" and somehow fall into the delusional trap of believing that purchasing books would somehow improve my strength and renew my motivation for a longer period. It's some kind of ersatz satisfaction, sort of how some people munch chocolate when they're unhappy. (Hey, I recently learned that "ersatz" is actually used in English!)
On the other hand, Go is a relatively inexpensive hobby, if you consider how many hours of frustra.. er, I mean,
fun you are getting out of it. Playing video games, golf, or even reading novels are all significantly more costly pastimes, especially once you've made some of the basic purchases, like a nice board and the books that everyone seems to have.
And if nothing else, it helps to support the Go writers and publishers, which in a roundabout way may also help to make Go more popular.