Math as a reason for the fall of the western empire is difficult to grasp. Do not forget that you are translating C into 100 to the zeroes are not important to roman numerals in that sense. As for the base form 0, I'm not knowledgable on roman math styles, but I suspect that there was a representation for 0, be it numaric or written (ie, none, zero, nothing...).
One of the discussions we had throughout my courses in college was advancements of Rome. For the most part it always came down to one thing. The Romans, for the most part, used knowledge that was already around, but used it to its maximum affect. The arch, what a wonderful thing, what happens when we increase its size....now what happens when we make many arches along the same path and connect them? See what I'm getting at? Romans used math, writing, poltics, warfare ideas that were already around, but used them to maximization.
One other thing on the Romans and numbers. I would never say the Romans didn't know how to use numbers or math. They could be maticulous book keepers, and the goverment definitely knew how to use numbers to determine taxation, grain prices.....granted it took Justinian in the Eastern Empire to correct the system, but that was centuries of decline in proper management. I was recently at the aqueduct at Pont de Gard in France, and it befuddled me to no end the precise use of mathmatics to achieve the (It think) 1 inch drop per mile span over a river valley.
There was one other thing I read here....give me a minute.
Ah, yes, the idea of electricity and romans. Why not? Are you saying that someone invented electricity? It's always been around, it only came down to understanding what it was, how to harness it and or create it. Keep in mind Romans probably still thought that lightening was a thing Zeus was throwing down at them, so.
As to the reasons for the fall of the western empire, goodness take your pick.... Barbarians, God's (Christian"s) wrath, inbreeding, lack of proper leadership, weather, lead pipes... it just keeps going. I like to simply think that it was a multitude of incredibly bad things happening all at the same time. Not a silver bullet of one thing only.