The German intelligence agencies often complain, that they are ill-equipped to deal with terror attacks efficiently because they lack the legal authority to use certain surveillance methods.
For example, they would like to have data retention like France and demand to be able to spy on people who they suspect of links terrorism, with a "Staatstrojaner" (state spy trojan) without having to consult a court first.
Germany is supposedly more vulnerable to terrorism than countries like France and the UK because of the ban of these surveillance methods. Yet Germany has seen far fewer terror attacks than e.g. France or the UK.
What are the reasons that in Germany fewer attacks happen, despite the country having more restricted intelligence agencies?