Modern society is not a thing separate from humans, its not something imposed on us, it came about in part because of our nature. We created it. That's I think the part where I can't ever see anarchy working on any scale significant enough to matter.... i.e. it's always human nature that will get in the way. Modern society is not great, and there's too much violence, poverty, pollution, hunger, etc. But it is much better than it has been for thousands of years. To progress beyond what we have now we have to solve the problems in the system and account for human nature and bad players. This is where anarchism fails, it assumes the problems are because of modern society/ the systems and that if we get rid of that human nature is inherently peaceful, we are not though. You and I may be, but it only takes a handful of bad guys to screw things up. I think we will eventually progress beyond the modern system we have and hopefully get to something better. I have a sneaking suspicion that the internet, AI, and robots will play a factor in that and that the future anarchists want is not dissimilar from the future we all want, but it won't be anarchism that gets us there.