They are a threat , but I would suggest nothing like Nazi Germany, if a real crunch is needed it would happen. IT ONLY TAKES SO MUCH FOR THE WORLD TO GET FED UP. If the world does get totally fed up there will be a bloody reckoning for this group and its like, but we seem too civilised to do the horrible deed , of going after them, to exterminate them, maybe we'll have to change the way we think , because this ISIS is as an abnormal organisation as anything we can think of today, and are totally out of the era in brain power.I agree with this to the extent that I cant see these countries developing industry or military to the extent of building a threatening global powers. You are wrong to dismiss them as a threat. The worlds apathy during the rise of Nazism, a perfect case in point. So similar its scary.
http://alphahistory.com/nazigermany/