There's a difference in cooperation between US/UK and USUK/Rest-EU.
Germany is littered with US military bases so I don't see how you think they are not cooperating much.
FVEY is on the receiving end of the pipeline, Germany only gets fed what the US wants to feed.
The Fourteen Eyes consist of the Five Eyes plus Denmark, France, the Netherlands, Norway, Germany, Belgium, Italy, Spain and Sweden. According to a document leaked by Edward Snowden, the Fourteen Eyes are officially known as SIGINT Seniors Europe, or "SSEUR".
There are 28 countries in the EU. Some countries among the 14 Eyes might even have elected leaders who are interested in having real autonomy and confidentiality in strategic government and industry areas, and would prefer not to have that leak out through an interlinked deep state.
I wonder if that prospect might not form enough of a threat that national governments might finally have the gumption to rein in their intelligence services.