Nah a set is a set. They wouldn't have been any more costly than any of the other ones. I think it is because the introduction of more characters would have blurred the story too much for TV. It works in the novels, but it is just too many plotpoints for TV. I think of the novels as the novels and the show as the show. They are both going to the same place, but taking slightly different routes to get there. Another problem is the show is about to overtake the books, so it may make sense to change things a bit inorder to not spoil things for readers. I just hope Marin actually finishes the damned books.
If they want more seasons though there is plenty of material there, or was. The end of this season and all character arcs will be caught up. At least Dany, Stannis, Jon, Arya and Cersei's for sure.
They don't want more seasons though. Period pieces like this are super expensive. Actor salaries increase dramatically the longer a series runs, and the production costs on something like GOT do not go down. By season 10 the cost would be untenable. This thing has a shelf life simply because of cost. They likely want to keep it under 8 seasons because of that. There comes a point when even a wildly popular product can't make enough money to justify the expense.
In fact, most of the sets are largely computer graphics, which has gotten really sophisticated. One of the producers has commented that he wished they had a budget to create more real sets for the benefit of the actors, who did about 70% of their outdoor shots against a green screen.
The rapid aging of the younger actors is already a big issue as well in stringing along a three-year story into 8-10 TV seasons. Also a problem is keeping some of these actors under contract for that long. Some are getting famous and popular and are receiving serious movie offers. Some will want out soon to pursue other opportunities.
Too much material. Books four and five are sloooow and very spread out with much superfluous material and without a lot happening to the main story threads. The producers cannot afford to lose a viewing audience to tedium. People will put down a tedious book and return to it later. But they will switch channels on a tedious film and never come back. George R. Martin is a very clever and imaginative mastermind of a fantasy world, but he is really not a very good writer.
Yeah. If Terminator 5 does what Paramount expects it to do then Emelia Clark will get really expensive.
