I think what you say is right, we should know that the west were uncivilized and backwards when the Islamic state was prospering, I think what propelled them to the top was dominating the trade with India and China without passing through the Muslim lands, through the west and south of Mount of good hope. The Mongolian conquest of Baghdad, which was the caliphate capitol, may have had some effect, before being driven off by the Mamelukes. So many reasons and factors, I guess.