It is not so far fetched as it sounds. We had a parlamentary inquiry after the Snowden relevations. The result of 4 Years work is a lenghty document detailing[0] (among other things) How BND and NSA work together on analysis and raw data processing. That does not mean that BND needs the NSA to bend the law (that one they can do very well on their own), but the cooperation between the 2 organisations is such that the bulk of analysis is done in data centers in the US, simply because the german intelligence services do not have the nessessary processing power.

One of the results is that the german intelligence services will get more resources to do analysis on their own in the near future.

[0]: https://cdn.netzpolitik.org/wp-upload/2017/06/1812850-ungesc... (page 484 ff.)