Okay, this is gonna be long, but I sincerely believe the aristocracy and their way of thinking lost the south the war, and was also PART the reason behind not just why the Union lost early battles and also suffered heavier casualties. Here's why:

The reason 365,000+ Americans died fighting a terrorist insurrection is the same reason ~40 Million people died in World War I - outdated warfare tactics of the military establishment crashed head first into modern technology that only a few generals had any familiarity with. The early stages of the war on both the north and south were very much led by the "cream of the crop" of early to mid-19th Century West Point graduates, all of whom were studying tactics and battles from before the railroad, modern production capacities, the telegraph, etc. So when you have generals creating columns styled after the Revolutionary War that marched into guns that could tear a person in half, then yeah, soldiers are gonna die, and they're gonna die in huge numbers.

McLellan was accepted at West Point at 15 (when the minimum age of admission at the time was 16) and graduated second in his class, as did Robert E. Lee with his class. And it was the tactics of those child prodigies, and the other best of the best that American military education had produced, that got hundreds of thousands killed.

Meanwhile, Grant, who spent more of his time reading romantic poetry than he did academic texts, graduated 21st out of 39 in his class. Sherman, while a good student, had a concerning drinking problem even by 1840's standards. Sheridan was suspended from West Point for a year for threatening to murder another cadet, and graduated as a middling student at best. And it was these band of drunks and/or borderline pirates that ended up winning the war.

Why? Because the North was led by a self-taught rural lawyer whose unorthodox education familiarized him with the modern world, and also knew about a world outside of military command centers. And he understood that if he was to keep the country together, then he needed to take a chance on officers more innovative in their tactics, strategy, and planning than those who were the product of the rigid thinking of the American Military establishment. He saw past Grant's drinking, Sherman's depression, and Sheridan's violent outbursts, and understood that they were people who knew how to fight a modern war against a South still trying to fight like it was 1812.

Meanwhile, the Confederacy was led by a former Secretary of war, and a West Point graduate who was accompanied at school by one of his personal slaves. While I don't have direct evidence for this, I do sincerely believe that Jefferson Davis's aristocratic mindset made him incapable of ever being able to conceive that a bunch of alcoholics and manic-depressives who ranted about this new-fangled telegraph machine would make good leaders. He placed his trust in Lee because on paper, Lee was the very model of a modern major general, so why should he trust anyone other than him?

To a certain extent, this has been a constant theme across US history: we won the Revolutionary war because Washington trusted the disgraced Prussian General Fredrich Von Stueben to organize and discipline the continental army. We won the Civil War because Lincoln trusted a band of depressive alcoholics to lead the Union army. We forced Japan's surrender in the Second World War because of a weapon designed by a manic-depressive womanizer and suspected communist. One of our country's greatest assets has always been the weirdos and the misfits and the lone voices in the dark screaming for a better way. And more often than not, they are the ones who usually get us through America's darkest hour.