The Walking Dead set through season 12

AMC is apparently not planning on ending The Walking Dead anytime soon. At a recent Producers Guild event, David Alpert stated that they are planning to run the show at least through 12 seasons.

“I happen to love working from source material, specifically because we have a pretty good idea of what season 10 is gonna be. We know where season 11 and 12…we have benchmarks and milestones for those seasons if we’re lucky enough to get there.”

Season 5 of the show is set to debut this October, but with this news I guess we can expect to keep seeing hints and premonitions for many seasons to come. It is no secret that the series has strayed from the comics a lot. However, the so-called "milestones" of the series have pretty much stayed true to the comics so far (ex. The Governor, Terminus, etc.). There is no telling how future milestones and introductions will be handled.
Screenrant has an interesting perspective and basically pointed out that in four seasons we have seen four different settings and tons of new characters. We started out with the camp and Atlanta, season two went to Hershel's farm, season three was Woodbury and the prison, and season four had the fall of the prison and the road to Terminus. The point being is, can this show survive a long-standing run if the setting is not changed up so much? There have also been complaints, especially during season four, that the show was getting very slow and boring.

I love The Walking Dead. I am saying that up front, but I don't believe this show can last too much longer. It's only as matter of time before the current characters get too old and have to die out. I liked season four when it did pick up, but as a whole it was pretty boring. I also think the introduction of characters only to kill them within the episode or an episode later is getting very annoying.
Similar to how I feel about True Blood, I am giving The Walking Dead a max of 7 seasons, maybe 8. If it goes beyond that it will just feel tired and the excitement will wear off. It's clearly starting to wear off already and how trends go these days the zombie trend will be over in a couple years anyway. There will be some new phenomenon to sweep through and grab everyone's attention.