The purpose of life, living, is probably about nothing. Or at least we can't comprehend much of it. Though we don't know much about the purpose we can at least take advantage of what we've got for free, life itself, and ride while it lasts. It can also be a hell of a ride if one knew how it's done. In an individual basis it may gift some with greater possibilities and others with limited possibilities. You cannot compare a healthy person to a disabled person for example.
In the world of religions, or at least the Monotheistic religions we face in the Caucasian world, life is supposed to be about purpose. It's definitely not about having a lot of good time while it lasts. But it's about believing in Allah, Mohammad, Jesus, or all of them put together. And if you don't, then you're doomed. This is at least how things stand theoretically. Proving this purpose of life is what religions call faith i.e. there is no proof, so either you are faithful or you are unfaithful. Therefore, faith seems to mean ignorance. Maybe just a Godless mind would call faith ignorance, as religious people would say.
Viewing the problem from a statistical point of view true religious fundamentalists are extremely few in numbers compared to the Muslim population of the world. Just imagine if only 5% of the Muslim men were religious fundamentalists and they decided to sacrifice their lives for the ultimate purpose, to go to heaven! Then we would have a 20-million-men army of devoted Muslims willing to die and there is no way the rest of the world would stand a chance in front of them, even with the most advanced weapons. So, the simple fact is that real fundamentalist Muslims who put their lives where their mouths are, are probably numbered in tens of thousands. But even tens of thousands is a large number, given that one of them can have the potential to kill 200 or more in just one suicide mission. The effects can never be globally catastrophic, but the images can do a lot of harm to the remaining Muslims who need to interact with non-Muslims.
So, why are there Muslims who go against their nature, their true genetic construction, and give up life for an uncertain purpose? My answer is quite simple. They have nothing to lose. There may be exceptions. But the vast majority of fundamentalist Muslims are people who have lives without ambitions, without prospects, and with almost nothing to lose. They see little chance of having a great, happy, enjoyable life on earth, so they prefer to go for the lottery of getting the promised life in heaven.
Nonetheless let's not forget that education plays its role too. High unemployment is not just a fact for Muslim countries. There are many non-Muslim countries that have high unemployment. Why don't they blow themselves up? They haven't been fed all their lives with conspiracy theories about America's exploitation of the Muslim world. If you ask an average Arab why America is a rich and powerful country there is a great chance of getting an answer like this “they are so rich because we are so poor.” Although this is just an unfounded lie highly regarded in the Muslim world, it seems to be a very persistent one, needing no proof. Ever since America has become powerful and rich most of the Muslim countries have got richer as well. Iran and Saudi Arabia became rich countries because of American dollars and American-protected system of capitalism.