I don't watch this, but from the outside looking in I don't think I've seen another show that went through the following arc as big as Game of Thrones has:
"A lot of people appear to watch and like it" to
"A few people started dropping off" to
"Half the viewers are now lost/bored with it and the other half are trying to keep pumping it" to
"A large number of viewers have the opinion 'eff this show'"
first of all, most shows go through the arc you just described. in fact, most things in life go through the arc you just described. game of thrones doesn't happen to be one of those shows to this point and have no idea how you came to that conclusion unless your entire sampling is kim carnes from goEMAW.com, in which case you're a Fake Sugar Dick (WARNING, NOT THE REAL SUGAR DICK!).
First off, I shouldn't have used the term "big". What I should have said is "as accelerated at GoT". Second, I've heard from multiple people from different parts of my life go from "you should watch GoT" to "don't waste your time, they drove it into the ground and you will feel like the time you invested in catching up was a waste". I had the same conversation with at 2 different parties this past weekend with multiple people agreeing with that sediment at both. Kim Carnes saying "eff GoT" and my computer rough ridin' up and making it looked like Nuts Kicked agreed reminded me of it.
My point was it seems like it's gone through the arc faster than any show I can remember that started as hyped as it did. Most of the people that were telling me to watch it last summer are now telling me if I'm not going to read the book first, then don't waste my time because it gets boring and weird.