RE: The real question is why so few do.
It seems to be ( as opposed to Christianity ), the degree of one’s devoutness to the Koran’s teachings is directly proportional to the degree of one’s embrace of ideological warfare.
There are 57 islamic states in the world. I don’t know how many of them are “moderate” in their imposition of sharia, et al, but perhaps the answer is that;
A)Because many already live under a system they agree with and thus have no need to fight,
B)They aren’t yet a majority in those places where they would like to rule,
C)They are simply apathetic about what goes on in their name
D)There are already many others willing to fight and die for them.