Quite the contrary. They're just getting started.
I think they're gone when we see the first prosecution for failing to pay taxes associated with BTC. I think the first group they would go after would be the traders who've made thousands, then the miners next because it seems like it would be harder to nail the miners, wouldn't it? Just a though. And you'd think they would go after someone big first, maybe like a pool or something?
Sure...the government will "arrest" one of their own agents with fake charges and even hold a fake trial to scare people (think Charlie Shrem), but anyone who isn't a total dipshit will see through it.