Now I realise it wasn't clear at all.
A disadvantage for the functioning of the empire, for its survival, for the cultural hegemony of the Romans, for a potential further expansion, and pretty much anything.
Many answers to questions like "If xyz didn't happen, could the Roman Empire survive until modern era? / conquer Easter Europe?", while being extremely long and detailed, all start with explaining how the slave labour was an essential part of the Roman society, and end up with how Rome couldn't maintain themselves anymore because more army means more resources which mean more slaves which mean more conquered people and so on.
That's one example. I know I'm a bit vague, but I assume some of you know the issue and don't need my full description. In case you don't, I'll search for links to some examples.
Ah.
Most historians don't view slavery as an essential part of the
collapse of the western empire. The late Roman economy is usually described as being "fine". The state was not short of funds until it lost control of actual tax-paying territory (and the means by which this occurred are still hotly contested among historians). For the most part, historians tend to view the end of the western empire as a combination of two things: failure of elite management and military catastrophe. The causes of both of those things are still a matter of dispute, but slavery was not essential to either one of them. In fact, it is very possible to construct a factually accurate narrative of the fall of the west without mentioning the word "slave" once.
The empire certainly didn't suffer from a
shortage of slaves. While Roman territorial expansion ended in the second century, Roman military operations did not. Up through the fifth century, Roman armies continued to mount expeditions into neighboring territory to destroy political enemies and take slaves. There doesn't seem to be much evidence that either a) the Roman economy started to fall apart or that b) this event occurred because of a lack of slaves.
So yes, I would say that these Quora answers
do exaggerate the situation. Although slavery was an essential part of the Roman society and economy, nothing about slavery caused the Roman Empire to collapse.
Which is absolutely mindblowing to me.
MacArthur was considered far more of a hero than he should have been. He should have been relieved by FDR in 1941.
Mac had a couple full-time PR people working for him when he was Army Chief of Staff in the mid-30s. -I believe that explains many mysteries about what he got away with for the rest of his life. He was just a big famous 'war hero' deal by his own design. He was already running for president 20 years before he was free to run, and woulda got it, too, if he'd been willing to do the work touring and kissing babies.
MacArthur never should have been brought back in the first place. He had the preposterous idea in his head that "the Japanese" feared his name so much that they would never attack the Philippines if he were commander. While I obviously enjoy the benefit of hindsight, I think that FDR's decision to end MacArthur's retirement was, apart from Japanese internment, his greatest miscalculation. Most other generals would indeed have been relieved after the sort of fiasco that MacArthur presided over in the Philippines.
1 But he was too politically dangerous to relieve, and instead he went on to establish a personal fiefdom in the South Pacific, diverting American resources, wasting American (and Filipino) lives, and lengthening the war with Japan.
Psychoanalysis is usually a bad idea in history, but it's hard to avoid the notion that he had a massive ego and was tremendously overconfident. When fighting against an enemy with little ability to maneuver, the overconfidence could be a boon, because things that would be risky against a wily and resourceful enemy were comparatively easy against a less-competent or underresourced one. But when fighting against an enemy that could take advantage of mistakes, like the Imperial Japanese Army in December 1941 or the Chinese People's Volunteers in November 1950, MacArthur's personality flaws led to real military catastrophes of the first order.
He could obviously come up with some very good ideas, usually about the operational level of war. While he never came up with "island-hopping", and in fact remained very wedded to outmoded ideas about land-based air cover that wasted time and lives and nearly caused two military disasters, he eventually managed to figure out a way to conduct the New Guinea campaign that bore some resemblance to military logic. The campaign was mostly pointless, but at least by 1943 it was well-run. And, of course, the Incheon landing was a risky and brilliant maneuver that he seems to have shepherded through almost entirely on his own initiative. The irony of MacArthur being the quintessential example of the American "political general" was that he had little understanding of either politics or strategy, even though he was quite competent at operational art.
1 = That said, the American military struggled with relieving higher commanders in the Second World War, even with cause. MacArthur kept his post after the fall of the Philippines. Bradley and his pet generals, Hodges and Patton, kept theirs after their open insubordination in the fall of 1944. Patton avoided relief over the slapping incidents in Sicily in the summer of 1943. Lower-level commanders, like Lloyd Fredendall or Charles Corlett, were relieved, sometimes with cause (Fredendall) and sometimes without (Corlett), but if you commanded a numbered field army or higher, you were safe as houses.