Modern historians like looking at things from different angles. Though this has been increasingly enforced along woke lines in the past generation, it is still a useful way to study. Previous histories were about who ruled and who won battles. While these things have enormous top-down effects on everyone else at the time, and often have long-term effects, sometimes they turn out to be incidental, while other perspectives tell us more. Religious and economic historians have long identified far-reaching effects that were more durable than whether a Henry or an Edward was on the throne in a particular decade. The study of rulers lends itself to the making of lists, which are nice memorisable items for students. Subregional studies of dukes and barons are the same thing on a smaller scale.
Military historians fell partly into the same ditches, though they were more likely to introduce changes in technology in weaponry and defense, which also informed our understanding of civilian technological changes. But it is only recently that historians have looked at social history in general. This has been driven by mostly female historians asking "What was life like for the women in this time and place?" and "What changes and continuities do we see over longer time-scales in that?" Studying marriage patterns, and whether women could own property, and whether they earned cash money are not things that changed overnight, as conquest or rebellion changed societies, but following those records tells us what we might otherwise miss, and provides explanations for puzzles. It also gives us a fuller picture of what life was like for everyone. When they ate, when they starved, whether mothers had any say in children's marriages, who provided music - we know much more about such things now. I think it is all to the good, and male historians have been largely won over to the new perspective.
(There may be a parallel here to Grim's recent post about actor and director Brit Marling, who has been a strong female lead according to the masculine definition of "strong," but wonders if some more specifically womanly strength and virtue might be preferable in movies going forward. Womens is womens and mens is mens, and we might learn something new.)
Historians develop specialties in studying coins, or architecture, or metallurgy, or transport of goods, or a hundred other niches. Amateurs will sometimes usefully pop in in such affairs, having become obsessed with trains or tools. Amateurs more usually immerse themselves in a narrow era, providing both market and support for professionals. Reenactors usually come for the battles, but stay for the homely details of camp food and cooking, boots and clothing, and interesting characters. Slavery is now drawing attention as a general topic, though the focus on the American version seems to have a pointed agenda. Sexual history is big, also with more of an eye to influencing current culture than to understanding others, I fear.
Useful things are still happening. We are used to studying the capital cities and central regions of empires - there's that succession of rulers again - but going to the frontiers and looking in both directions can tell us much that is new. As the skin of a human can be considered an organ, so too can the boundaries bring new things into focus. If one is studying the British Isles and Roman Britain, the skirmishes with the Scoti and the Picts seem like a local affair, leading to purely local questions of descent, language, and economy. Yet the same issues played out along the entire boundary of the Roman Empire, with Allemani and Franks in Gaul and across the Rhine, Visigoths across the Danube, Huns across the Caucasus, and desert tribes just outside the fertile areas of northern Africa.
Contemporary historians writing from the interior saw all these groups as exotic barbarians, wild tribes with little organisation beyond raiding and the most minor of invasions. Yet the soldiers and commanders on the frontier saw them differently. They paid one tribe to attack another, and over time this could turn into a type of tribute by the Romans to those tribes in a sort of protection racket. They would also hire them, individually or in groups, as soldiers in the Roman army, for a few years or a career. They traded with them. They raided into the barbarian areas, both as a show of force, but also for plunder. Coins and goods from Rome were concentrated at the frontiers, where the soldiers had to be fed and paid and have things repaired. Twenty or a hundred miles back from the Danube toward Rome was a poorer, if safer area. It was harder to get goods to market from those spots. Crossing a river or a string of forts in force might be difficult, but money flowed along both, giving prosperity to the area.
The frontier might be the more dangerous area, but it was also the more sophisticated, with many languages spoken, ideas encountered, and luxury goods found. The boundary also changed what happened just on the other side. Smaller groups who were often at war with each other would band together, both for raiding the near-interior of the empire and for protecting themselves against raids. After a few generations, those tribes would include many who had fought as Roman soldiers, including officers and those who had been sent to wars in far lands. The distinctions between Roman and barbarian became less clear. The boundary would become something of a mirror, as the better-trained and more prosperous Sueves or Goths, who would have some knowledge and experience with other cross-border "barbarians," would be more concentrated along the Danube, and have information about what was happening on the other side, all the way to Rome.
When Rome was unstable, as in the 3rdC when there would be a new emperor every few years, troops would be drawn from the border and the larger confederations on the other side would find raiding or exacting protection money easier. They were not so used to cooperation that they could conquer territory or sack cities, but the foundations were laid for that to happen later. The Huns, from deeper on the steppe, actually were organised rather than the seeming wild bands the Romans imagined them to be. It was not accidental and bad luck that they invaded the empire across the Caucasus and to the Danube at the same time. They had plenty of information about the vulnerability of Rome and attacked in coordination in search of plunder and tribute accordingly.
Rome was eventually overtaken by armies it had partially trained and caused to come into being by its own actions. Those barbarians were not amazed at Roman wine, armor, and coins. They had grown up with these things in their lives. Though they may have been amazed at how much was concentrated there, and perhaps at the art and architecture.