Pretty much the same argument could have been made of the Germanic barbarians who conquered Western Europe. They brought little original, at least in material things, to Western civilization. Instead, for most of a thousand years they attempted poor imitations of the Greek and Roman civilizations that preceded them.
In 1400, Western civilization had climbed back to a point roughly equal to the Islamic, Mogul, Chinese and Japanese civilizations. The interesting point is not that Islamic civilization stagnated at that point (as did the others), but rather that Western civ entered a 600 year period of amazing innovation and expansion which continues today.
The Moslems did do incredible work in creating a synthesis of Greek, Roman and Persian art, architecture and science and were significantly ahead of Western Europe from about 800-1400 CE.
Let's not get too cocky. Western civ can decline and fall as others have before it. Not because it's overthrown by outsiders, but from its own decadence.
The relationship between Islamic and pre-Islamic, Arab and non-Arab civilizations in the Near East, is not dissimilar from that of Christian and pre-Christian or Germanic and Mediterranean civilizations in Europe.
One could also look at the last 400 years of Chinese or Indian history and be unimpressed, but this would be to miss their great achievements in premodern times.
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Our civilization has had many great achievements, but we ourselves aren't in most cases responsible for them, and our generation or our children's could be the one that lets the whole heritage go smash. Remembering what came out of Babylon or Mesapotamia millenia ago, may help to keep our heads from swelling too much.