Can AMC’s The Walking Dead survive without Rick Grimes? The ratings aren’t encouraging, to say the least.
It’s very common for any hit TV show to shed viewers over the years, especially if that show is serialized. For procedurals – like your NCISes and SVUs – it’s a little easier to weather the storm of time and hold steady. The cases and crimes are the true draw, and the inertia can be comforting if you’re looking for something to only half-pay attention to.
But shows that specialize in intense serialization – and not those serialized-procedural types, like The X-Files and Supernatural – tend to peak in the middle and wane toward the end. Certainly, there are exceptions. There are fully serialized shows that actually grow and grow, going out with a bang and getting their best ratings ever during their endgame, like Breaking Bad and (assumedly) Game of Thrones. But those stories were always building towards an ending. Walter White had to come crashing down. Someone has to win this “game” of thrones.
Source: IGN.com Here's When The Walking Dead Really Started to Lose Us