And extremist Muslims may have the goal of bringing their faith to the entire world, but they haven't the means, any more than Christians in previous centuries had the means to bring their faith to the entire world (although they most certainly tried!). Or, really, you can insert pretty much any major religion (including some faiths no longer in practice) into this: most cultures have tried to force their beliefs onto the rest of the world in some form or another and have failed. If anything, I'd say Western culture has been the most successful at it (and not entirely through violent means, either -- non-violent means seem to work the best).
This is a totally different world than when the Christians tried to force people to Christianity, can't be compared IMO
As far as, "they haven't the means", well I don't know about that as we all depend on their oil, and it brings them gazillions of dollars. I think many of the terrorists and terrorist countries are very well financed.