My point was, notice how none of the major Western civilizations was ever destroyed by natural forces? But if there was a severe thunderstorm on record when an ancient culture fell, it was always the weather.
Actually, Jared Diamond argues in
Guns, Germs and Steel that Roman civilization was pounded pretty hard by a lengthy cooling period we call the "Little Ice Age". Shortened growing seasons caused crop failures, eroding the empire's economic base, at the very same time even worse failures and outright glacial growth were pushing tribes from Central Asia to migrate to warmer regions. So invasions from without, combined with less ability to support soldiers, combined with a lot of other factors, pressed that civilization beyond what it could bear.
He was pointing out in that book that types of plants that allowed a high amount of food production per acre were much more prevalent in other places, and that the larger creatures able to be tamed and worked were few. Apparently you can't make a llama do everything you need it to, but you can castrate a llama and use it like a guard dog against woodchucks, muskrats, and coyotes.
These are important arguments, but even more important was the relative latitude distances between Eurasia and the Americas. Eurasia has really wide bands having the same climate, meaning a crop or an animal domesticated in one place could be planted in many, many other places. This created a very wide band of competition for arable land, ensuring that nobody could conquer the entire thing for any length of time, such that wars of conquest were common. Any group that gained an advantage would quickly export it to other groups, by hook or by crook.
In the Americas, in the other hand, the much smaller climate bands (due to the north-south stretch, rather than the east-west stretch of Eurasia) ensured that each group was specialized to its own area. Conquest would therefore be much less of a threat, since each group would find itself at a disadvantage trying to produce food in their neighbors' territories. Maize was a fine crop, and resulted in a fair degree of development in Mesoamerica, but it took literally centuries for strains adapted to cooler northern climes to arise. At any rate, any (agraian) civilization was destined to be fairly local in scope, and therefore much more vulnerable to local disasters.
At any rate, none of this has anything to do with the Dwemer. My theory about them is that, when various factions fought over the Heart, they fought over the timeline, in a scene similar to that time fighting scene in Bill and Ted's Bogus Journey, or a joke Dr. Who sketch I once saw. The Dwemer's timeline just plain got lost in the shuffle, is my theory.