I can enjoy the story without keeping the books. But knowing where the story goes will make it hard to enjoy and re-reads. Plus, I look at my collection as a family resource. Someday my kids are going to read my collection, and while I don't mind having gaps and holes in storylines, this is one story that I'd rather have the whole thing or nothing. Because at some point, if I keep them, they'll be read, and someone will ask "what happens next?" If they encounter that on their own, they can make their own decision to pursue it further.
I think, aside from touching on what are my greatest personal fears in real life, this series has taken a direction I just don't find compelling. Zombie stories can be many things, but the ones I'm most interested in include some aspect of the best of humanity. The zombie can be seen as mankind's worst inclination, distilled down to a near-mindless husk that cares more for it's own engorgement over self preservation. It goes beyond selfishness, into a realm of desire to the exclusion of everything else, leading the body to do terrible, terrible things.
In the survivors, you want to see humanity's best. They usually aren't the best of people, and often are among society's outcasts. But in the face of true depravity, you hope to see glimpses of the greatness that people are capable of.
Walking Dead now just seems to be an examination of all the worst aspects of people. It's not for me. 10 years ago, 20 years ago, I'd probably have felt different.