Sadly, I think the NSA will only be reined in down the road once more Americans lose money because the rest of the world decides American tech is inherently less secure due to NSA meddling. It'll be about the money instead of any concern for our beaten, tattered and absolutely despised US Constitution.
Until the NSA can be commandeered to be in service of the American public instead of being a corrupt lapdog of corporatist scumbags, they will continue the path of unconstitutional and corrupt suspicion-less surveillance instead of targeted surveillance that can actually protect the public in some circumstances.
Maybe further down the road they can even focus on helping the public to be more secure, but I'm not counting on it considering how profitable and powerful it is to be able to destroy political adversaries (and activists), pluck business secrets and generally fuck over anyone and everyone who is unfortunate enough to cross their corrupt paths.
I guess it all comes back to taking over our own government and getting to the root of the evil in the first place:
Gotta start somewhere...