There's been outrage in the past, but it's generally been limited to the tech community and didn't last long because it dropped out of the news quickly. This time the government openly acknowledged the mass collection of everyone's phone records without probable cause, and continued media coverage has allowed it to build momentum. I think many people have been very upset about it for a long time, but everyone else seemed to show apathy so they did too, because if no one else seems upset, it's hard to feel like anything can ever get done about it. When everyone is angry, there's more chance of getting something done.