I think that in the case of Anita Sarkeesian, she will be around as long as she is being loud and attracting attention whether it be positive or negative. As it has already been stated in this thread and in some of the videos responding to her, her argument isn't very strong. Whether she is right or wrong isn't the issue, she simply doesn't possess the ability to effect any real or lasting change. Eventually the people who hate her will grow bored with her and the people who support her will realize she doesn't have anything new to add and will move on to the next loud person who wants to draw attention to themselves. She is an internet sensation, just like the Numa Numa Kid was back in 2004 or "Gangnam Style" was last year.
That was my initial thought, too, but seeing that she had a TED talk and raised $120k+ on Kickstarter makes me wonder if she's going to become the new figurehead for feminism. This is how activist cults get started. Or they could eventually turn on her and devour her, too. It's a very interesting phenomenon to watch happen at this point.