The crisis of the third century A.D. demolished this world and led to a social and economic restructuring of late Roman society. In northwestern Europe it produced an oligarchy of a few exceptionally wealthy families. The elevation of the extremely wealthy to oligarchic status is happening differently today, but the outcome of that elevation could follow a similarly disastrous course.
The social and economic restructuring of northwestern Europe in Roman times began with a series of disasters and wars not entirely unlike the Great Recession and multiple attacks and wars that afflicted the last two presidents. These shocks devastated the population and sharply reduced production.
Since the tax revenues from a diminished empire could not meet such increased expenditures, the emperors started paying soldiers and suppliers in depreciated coinage. Credit and commerce collapsed under the resulting inflation and distrust, barter returned to poorer parts of the empire like northwestern Europe, and land values there plummeted. Peasants fled from soldiers and vagabonds foraging for food, the urban middle classes floundered, and the surviving towns and cities, barely hanging on, could no longer protect the countryside and its farms.
Only the very rich--Roman senators, imperial generals and the like--had the diversified investments that allowed them to escape the poverty and dangers that engulfed virtually everyone else.
These wealthy Romans acquired huge tracts of land at bargain prices, becoming the owners of northwestern Europe's most productive assets. They could offer protection and aid in return for loyal service, and desperate men flocked to their employment (mostly tenancy). The emperors now had to wheedle taxes and manpower from these great powers. The resulting bargains gradually sapped imperial power, and after the Vandals sacked Rome itself, in 455, the last emperor soon departed.
Northwestern Europe's new social and economic structure consigned the vast majority of the population to miserably impoverished lives.
This concludes todays history lesson.