Sleeper cells. Have they been here for years and years?
The jihadis, who brutally compete with each other in the Middle East for influence, have become the underlying ethos of young activist or get in the mix minded Middle Easterners for two or three generations now.
Hasn't happened in a vacuum. Huge amounts of money go with these ideologies and a messed up global outlook permeates and into their media & guns.
Their backers would naturally be the older more empowered and strategic sugar daddies, far from the fray and effective prying eyes.
Unfortunately, money buys experts, opinion, impressions and then the conventional wisdom gets skewed to accept concepts that don't work as well for mitigation.
It won't end until instilling hate doesn't work as a strategy, even then strategically, it's the cutout way they get to play.
Sorry if this makes no sense, but not much does when Paris, of all places suffers this way. The cells haven't been sleeping, nor are they just cells.