I am going to cherry pick your post here Tundra, forgive me. Gibbon, in my opinion, is not a credible source any longer for the decline in particular, anyway. I find his first five volumes to be very comprehensive and an accurate study of the sociopolitical status of Rome throughout its history. However, his ending thesis regarding Vandal invasion is wrong, in my opinion. He attributed it to a loss of morality, which stemmed from their straying from Catholic faith. This was clear and uncut propaganda from Gibbon, an unfortunate inclusion in such a masterful piece of scholarship. His faith obstructed his objective, academic conclusion. Please do remember, that this work was finished and published during the most tumultuous time in human thought: the Enlightenment. Gibbon's work served as a counter to many philosophes' works such as Voltaire's Spirit of Nations and Treatise on Tolerance. There was as much allegorical work as there was historical, which is why we must be cautious when using Gibbon's work in academic settings regarding the fall of Rome as an idea. While I believe that Gibbon's monstrosity of a work is a very important piece of understanding Rome and its historiography, I cannot possibly use his final thesis as fact. We can use it, of course, as a great foundation and as a particular lens or viewpoint. But, I would be apprehensive about siding with him or even using his morality question as a basis of reason when determining the cause of the fall itself.