Why would Muslim communities in the US behave any differently than those in Brussels and Paris. The terrorists were given solace, refuge and support within those enclaves which are very difficult to police. Given the politically correct policy not to profile and the use of encryption technology, the terrorists here have the same environment they enjoy in Europe. Stopping lone wolves or brother tandems is very difficult.
There are no Islamic neighborhoods other than Dearborn. Most are fairly spread out at this point.
A number of the Muslims here in the US differ from those masses coming to Europe. For example a number of Iranians came to escape the Ayatolla when Iran went hard Muslim. Others have also left because of differences with their oppressive home governments, and were not necessarily the rather poor. France fought a vicious war in Algeria, there are no doubt unhappy Algerians living in France. Just one example I am aware of.