It's not unheard of for a AAA sandbox game. They can rack up a lot of expenses on audio (voice work, music) and the time/effort it takes to make that large of a world with that many different items. Toss in a tortured development process and the cost can skyrocket further.
It's often neglected, but just like movies, advertising can account for a significant portion of a game's budget. I want the game, but refuse to buy it. Wah wah. Thinking Alice in Wonderland looked a little flat on Blu-Ray, Ray