As I understand it, real life terrorists are rarely competent enough to make this a major worry.
Moreover, organized crime groups, which in real life are much more serious problem, are quite adept with advanced technology. They set up their own radio communications networks and use aerial and submersible drones.
Well, sure, in that terrorist organizations are, by definition, a subset of organized crime, so that the problem they pose must be strictly less than that of organized crime more generally.
...get elected as politicians or use their cash for more productive uses such as regulatory capture.
> Moreover, organized crime...
...simply used their captured politicians to make their activities legal. Why use cloak-and-dagger tricks when it is cheaper and easier buy the organizations that get in your way?
A ban of end-to-end encryption will need to be enforceable. What will LEO do, if I come up with it? Bust my house? That's unthinkable in Europe. Enforceability also means that all communcations must go unencrypted. This merely would kill all online commercial activity.
Then you have the massive cost of re-issuing all the keys.