If you're someone who uses the Internet, the NSA can take over whatever you use to browse with and have their way with it. If you don't, well that's what their interdiction program is for.

The thing is though, the economics of 0day indicate that the more you use it, the more likely it is that it'll get burnt, and supply is limited.

They can certainly hack anyone, but it doesn't scale, so they can't simply hack everyone. They can maybe use these techniques on a handful of targets per year, so they make it count, but most of their intelligence comes from the data we all give away for free every day.