And yet having a great civilization in the past can help give incentive to strive for a great civilization in the future. China (chiefly the PRC) and India look at their powerful pasts, and then--somewhat smugly--toward the future.
Oh, the islamists do quite believe they're striving very hard for a great islamic civilization. Only problem is that what they consider 'great' is pretty much some of the most miserable existence imaginable.