If today's modernists argue that Christianity and science was incompatible. Then one can surely argue that Islam and science are not as well. However this is not what they say, they may allude to this sentiment but like all post-modern logic, they will not come out and say it only will offer a token acknowledgement of their leadership in the sciences a long long time ago. As the dawn of science advanced further and the enlightenment took hold in europe, Islam began to fade and has begun to look inward and found that the world being forged by western ideas where in fact incompatible with their stated idiology. had it not been for the Ottoman empire, Islam may surely have been relegated to the dustheap of history
Of course the Mongol Horde had nothing to do with the collapse of the Islamic Empire.