Yes, I think Sandra Bullock should be paid $70 million for her efforts in Gravity. If she makes less money the ticket prices at the box office won't be going down. The film company doesn't need to make more money. I see no reason why a highly talented actor should not be paid very well.
As long as there are people going to the theaters or video stores to buy the video and see it, this is totally justifiable. The only way it might be problematic is that it invites inflation of movie ticket prices and if she took less, the video itself might be able to be cheaper to see.
If Sandra Bullock is getting paid 70 million for her efforts in the film, they must be expecting the film to do pretty well. Her contribution is paid based on the overall profits of the movie. Although her part is just one in many, Her skill as an actress is arguably invaluable. The market dictates her profit margin. If we want actresses to get paid less, don't pay for their movies.
Sanda Bullock brought a great deal of talent and marketing power to Gravity. While the movie might have been popular without her starring in it, a good deal of the box office profits are attributable to Bullock and her performance. Since she is a huge part of why the movie made so much money, she deserves a sizable amount of the profits.
I believe that the amount of money that Sandra Bullock is about to make for the film Gravity is justifiable. While a lot of people may think that she is being paid way too much for acting in a film, that money is due to the deal she made with the studio.