@Tonifranz: the majority of people in those situations that benefited from empire were the elites, and (if it existed) the middle class.
Galba Otho Vitelius specifically said
the people living in the metropolis, rather than the metropolis itself.
Take the UK, for instance. Whilst the poor in the colonies laboured to extract/produce primary resources, the poor in the mother country laboured to turn said resources into manufactured goods.
The rich benefited. But so did the poor.
Let's take Rome, for example.
When the Republic took it's first major acquisition, Veii, it settled the landless poor on plots of land, giving them farms, and making their lives much better.
As it expanded throughout Italy, the Republic confiscated lands from it's defeated enemies, and a lot of those lands were given to landless citizens in Rome as farms. Why? Because only those who owned land could become soldiers, and to settle them on land was to expand the base of recruitment.
And also, as it expanded, they founded lots of colonies to hold the new territories. Who populated the new colonies? The poor who would have nothing to lose from leaving Rome. Colonies were founded all throughout the Republic, giving the landless plots of land to farm, making their lives better.
From what I read, even though the second century BC witnessed the rise of latifundia and the decline of small landowners in Italy, small farms in Italy actually expanded during the 1st century B.C.
The reforms of the Gracchi actually did give lands to landless peasants, even though the Gracchi themselves were killed.
But more importantly...
Marius settled his landless veterans of plots of lands in Italy.
Sulla settled his landless veterans in plots of lands in Italy.
Pompey settled his veterans in Italy too.
So did Caesar. And Antony. And Augustus.
And you must remember that Augustus settled about 30 legions after Actium.
Where did the lands came from to give to these landless soldiers?
From the Ager Publicus.
But also from the confiscated estates of those who lost and those who supported the losing side. Or because their lands were just outright confiscated like the estate of Horace for the settling of demobilized soldiers after the Perusian War.
After taking Egypt, Augustus simply used Egypt's wealth to buy lot's of estates in Italy and settled tens of thousands of veterans of individual plots of land.
So yeah, a kind of land reform happened in the first century, in that the estates of the losing sides were given to landless men, aka soldiers who served in the armies. And it didn't even require being soldiers of the winning side. Octavian even settled the soldiers of Antony's armies after Actium.
Now in Rome itself, grain became cheap and subsidized, then became free. Who benefited? The poor in Rome who received it. Who paid for the free grain? The provinces.
During the empire itself, the plebians in Rome gained many benefits, from a fire brigade, cleaner water from aqueducts, a better diet from importation of foods, free entertainment, free baths, also free grain, free meat, free olive oil. All possible because of Rome's empire.
Then there is the
alimenta, a welfare program that helped orphans and poor children throughout Italy. It provided general funds, as well as food and subsidized education. The program was supported initially out of Dacian War booty, and then later by a combination of estate taxes and philanthropy. In general terms, the scheme functioned by means of mortgages on Italian farms (
fundi), through which registered landowners received a lump sum from the imperial treasure, being in return expected to pay yearly a given proportion of the loan to the maintenance of an alimentary fund.
Now are you going to tell me that poor people in Rome did not benefit from empire?