<quote> One cannot, of course, “know” this in the same way that one can know the date of the battle of Poitiers; applying economic analysis to the spotty record of commerce during late antiquity is a tricky business. However, as can be seen in a subtly reasoned 2003 paper by two development economists, Ronald Findlay of Columbia and Mats Lundahl of the University of Stockholm, it is compelling, as well, despite its reliance on a number of simplifications. </quote>
This would be like saying "well drunk driving doesn't cause accidents because I drive drunk once and didn't get in a crash"
Why other events did not have the same effects are very interesting questions for economic history.