It's almost as if there's some mutually beneficial relationship going on between US and European intelligence and military agencies, and the anger of Europe's governments is mostly political sideshow...
The USA works very hard to radicalize anti american factions within a country. If the choices are US backed dictator, or religious nutjob, its not much of a hard choice.
I can understand feeling morally opposed to it, but a realist might tell you that it's important to spy on the German government simply because it's a powerful actor, even if it's an ally of the United States.
That realist would be a fool who takes the exasperated statements of politicians at face-value. Were any long term trade agreements threatened? Embargoed in a way where they actually did it, not just talked about it? Was military cooperation withdrawn, diplomatic ties severed?
Absolutely none of this happened. A lot of words happened. Mysteriously, for exactly as long as Snowden was in the news right up till Russia invaded the Ukraine.
Explain me why you spy out german government. Is Merkel a potential terrorist? Yes sure.