Of course it has.
How do you persuade people who are obsessed, to the level that they will kill themselves for their 'cause' though?
The fanatics are not going to listen to reason, and although small in number, can wreak substantial havoc, as has been demonstrated on both sides of the pond.
Unless there is help from within the Muslim community, identifying and stopping these people is impossible.
There is a huge problem here, which is that a small number of people, working in isolated cells can be undetectable, until something happens. Manufacturing a car bomb is relatively simple. I would expect that to happen. (It has been tried, but due to 'technical difficulties', thankfully none has exploded.)
As I see it, the problem is insurmountable, it is something we are going to have to learn to live with.