It seems to me that one flaw in the interpretation of history by historians is that they often overlook economic factors. Historians seem often to take a phenomenological stance towards economics. The economy of a region, a population or an empire just is and just happens. It is a consequence of circumstances rather than a cause of. It is what it is. This is a shame, because the way a population treats its economy is a good predictor of its success.
There is an elegant and surprisingly simple explanation for the fall of the Roman empire that is criminally overlooked by many such historians. In fact, you can go to the dedicated Wikipedia page right now and ctrl + f “price controls”, or “debasement”, and hear that unsatisfying sound your browser makes when it finds nothing. On that same page, under “Reasons”, there are just two. One from Edward Gibbon who says it is simple and obvious why the Empire fell. He then gives a convoluted explanation that involves power, Christianity and oppression of the people. Granted these causes were important in the continued downfall, I believe they were not causal.
Near the end of the Roman Empire it had achieved a great degree of division of labor. Early in a civilization’s lifespan, people tend to produce everything they need by themselves. They then start trading for some things which gives them more time for leisure and specialization. This positive feedback loop continues, continually increasing the division of labor until you have a shoemaker, a baker, a builder, a sculptor, et cetera. It is unthinkable that a subsistence farmer would also be a shoemaker. He has animals and crops to tend to. He does not have the time. Trade buys him time, and with time one can specialize, to buy more time, to specialize more, and so on.
To make shoes, the shoemaker needs leather, which he gets through trade. When a pair of shoes is done, those should be traded once more. To trade, both parties need to be at the same place. So specialists and traders find it helpful to be at the same place all the time. That’s how you get a city. The Roman empire had a bunch of these cities, with highly specialized workers producing and merchants trading. The city needs to eat as well, of course. But food doesn’t grow in cities. It grows outside of them. Food is produced outside of cities, other consumer goods are produced inside.
In the empire the food of choice was wheat. Wheat was grown in large fields outside of the city. Some of those fields belonged to small farmers, but a lot of fields were owned by wealthy land owners, whose fields were tilled by slaves. The wheat produced here went to the city, where it was sold. You couldn’t just name your price, however. There was a range of acceptable prices for wheat, and the empire was quick to step in if they found you overcharging. At some point even fixed prices were adopted, which meant every Roman citizen could buy a certain amount of wheat at no more than a certain price. If the harvest was good, the price may drop due to oversupply. But if the harvest was bad, the price could not rise, resulting in shortages everywhere.
So the city relied on wheat, which they bought from outside the city at a fixed price. At the same time, emperors were having problems paying their bills. They solved this problem by debasing the currency. You can try this at home yourself. Simply take a gold coin, melt it down, and mint two new (smaller) coins from the same amount of gold. Now declare the new coin official currency and you’ve made yourself twice as rich. If you want to get fancy, you can add in some copper to make the coin weigh the same and hope nobody notices.
To the emperors dismay, it turns out you don’t actually need anyone to notice. Those new coins that enter the money supply inflate it, and prices rise. Slowly but surely prices started rising everywhere in the empire. Except for wheat, that price was fixed. But that made farming wheat no longer profitable. So farming stopped. Then the cities ran out of food, so people left.
With the wealthy specialized workers from the city leaving the city, farmers had to make their own things again. Wealthy land owners retreated from the city to their big villas, where they hired shoe makers and bakers and everyone they needed from the city. They were paid in wheat, which the villa had plenty of. Some had no skills, like recently freed slaves. Those could work the land and earn their wheat that way.
If this design reminds you of the Manors of the medieval period, that’s because this is that. The Roman empire almost seemlessly transitioned into this part of the Medieval period, and no Barbarian had to lift a finger. The blame is with those in charge of the mint, and those who restrict free trade. Of course the Barbarians did finally conquer Rome, but that’s probably not hard if everyone is starving.
Where’s the nuance?
Of course there are hundreds of small events that helped in the eventual fall. Just like old people often die of the flu. It is then technically the flu that killed them, but the flu was only able to kill them because they were weak. Countless flu viri will try to conquer you, just like countless attackers tried to conquer Rome. The final victor just came at the right time, when Rome had crippled its economy and uprooted its productive infrastructure. Barbarians didn’t kill Rome. Rome did.