What if the Napoleonic Wars had been fought with the same savagery as the Thirty Years War?

About 10% of the total population of Europe was exterminated in the Thirty Years War, about eight million people. In the most critical areas of Germany where the Thirty Years War was fought, population dropped by 50%. In other words, genocide was the standard approach to warfare in the Thirty Years War. As following the Black Death centuries earlier, total European population dropped following the Thirty years War, from the previous century. In contrast, total losses from the Napoleonic Wars, 150 years later, out of a much larger population base, with a much higher degree of industrialization, much larger armies, and deadlier military technology, were perhaps three million people. Why were the Napoleonic Wars so much less deadly than the Thirty Years War? The Napoleonic Wars lasted almost as long as the Thirty Years War. Humanity's capacity for destruction was clearly much greater. Historians note that following the Thirty Years War, European nations deliberately avoided total wars of annihilation. In particular, annihilation of civilian population, was generally avoided, if possible, and if convenient. The Thirty Years War probably represented a watershed in terms of the ability of invading armies to quickly, readily and easily annihilate civilian populations. Portable heavy cannons and artillery, convenient hand held firearms were making sieges of towns and fortresses much easier and quicker than they had ever been before, in human history. And, once subdued, these technologies made it very easy to kill human beings en masse. So, that's exactly what invading armies did. They killed everybody. Literally, everyone. Up to a point, the religious nature of the wars provided a rationale for that. The enemy where heretics, and heretics had to be condemned to death to purge their eternal souls and save them from eternal hellfire. But, when you come right down to it, most people would exterminate everyone else on the planet, given the chance. So, really, this behavior simply represented the fact that our technology had finally caught up with our natural aspirations. However, there is a downside to exterminating all your enemies -- that is, everyone else, other than yourself. First of all, everyone else is very likely to do the same thing, to you. So, you won't be around to enjoy your triumph, probably. Also, with everyone dead, and everything destroyed, there really isn't much to enjoy yourself with, is there? And, this is what the "victors" noticed, at the end of the Thirty Years War. There wasn't anything, or anyone, around, to really "win". So, the nations of Europe decided that however appealing exterminating all your enemies might be -- genocide, that is-- and however possible it might be, ultimately, it doesn't achieve anything very useful, at all. So, European nations decided not to do that anymore. Genocide, that is. As a standard method of warfare, anyway. And, to a large extent, they haven't really engaged in this kind of systematic destruction of civilian populations en masse, since. From time to time, yes, for practical reasons -- Sherman's march to the sea, in the American Civil War, for example -- or on whim, with a particularly disliked group like Hitler did with Jews and Gypsies. But, as a standard approach -- "Hey, we've taken the city, time to kill everyone in it" -- no, not really. Doesn't work very well. So, although the Napoleonic Wars were certainly total, industrialized wars, just like the Thirty Years War, or, perhaps, much more so, they were, actually, much less destructive. Because, total war or no, European nations did not see any purpose at all to going back to exterminating all civilians they could get their hands on, any chance they got. Nobody won, then, ever. This may have some relevance to nuclear warfare. After all, when the U.S. first got hold of nuclear weapons, they used them the first chance they got, and loved the results. Total Destruction! Wow! Great! Then they thought about that a bit. "Hey, if we could destroy them totally, why, by God, somebody else could destroy us totally, too!" Not good, that. So, the U.S. decided they'd rather not use them again, if possible. They thought about it, during the Korean War, but, decided against it. Possibly because the USSR had nukes, by then, and they'd probably use them too. And, over time, although nations have threatened each other, they seem most disinclined to use nuclear weapons, ever, even against nations that don't have them, whatever those nations do, or however threatening they may be. Because, ultimately, even national destruction, and personal death, really aren't as bad as destruction of the entire human species, are they? But getting back to the Napoleonic Wars. Suppose, Napoleon et al. did decide to do it the Thirty Years War way. Kill any and all civilians you can get your hands on, every chance you get. So, let's say some 50 million dead out of a total European population of 150 millions. A third of the total European population. I think this would have been perfectly possible, if they'd really wanted to do it that way. Effectively, continental Europe would be thrown back a century. Britain would be totally dominant, as the only untouched region. Probably, Britain would have been powerful enough to reconquer America, and establish a truly universal world empire. It might have lasted for centuries. Any thoughts?