ADHD impacts many people's most basic functioning. Routine chores like laundry or dishes pile up, you lose tools you need for the task at hand, you forget to do things that are necessary to maintain your health, and more. ADHD also has adverse effects on emotional regulation that can cause interpersonal conflict. None of these things would be alleviated under a different economic system.

We tend to focus mostly on the productivity gains of medication, but anyone who takes it will tell you how much it's improved their personal lives as well.

I think the complexity and pace of modern society is causing these issues.

A double-edged sword. If you lived a life alone in the forest you wouldn't be beholden to anyone else, and thus something like missing an important date would not matter one bit. However you choose to spend your time is not going to affect anyone other than yourself, so it's all good.

But, on the flip side, a common trait in ADHD is hyperfocus, which our complex modern society is very amenable to. Letting others help means not having to worry about growing the food to feed you and preparing your shelter to shelter you. That means you can turn all of your attention to something more productive, more complex, that is beneficial to all of society. In fact, many of the people who have done world changing things are considered likely to have/have had ADHD. It seems probable that such pursuits would be impossible for someone who does not have hyperfocusing abilities. There is only so much time in the day.

Perhaps having the ability to change the world is not an issue at all and is actually the ideal state? And if that means you forget to pay a bill and someone gets pissy about it... Oh well? That's their problem. As with absolutely everything in life, there are tradeoffs to be made. You can never have it all. What would we say is the most suitable trade to make here?

Complexity was never an issue for my ADHD. Lack of interest in things I do not find interesting leading to forgetfulness and the inability to keep small, uninteresting details straight was the issue.

They actually don't. They create a short term boost to certain aspects of cognitive functioning. While, in theory, this improves performance, in practice, it is often bottlenecked elsewhere.

It's like giving a rally car more engine power. Without the ability to get that power to the wheels, it's, at best, useless, at worst counterproductive. It might feel like you have more speed, but your lap times will be worse.

On top of this, you have the body's homeostasis systems. In a normal brain, they will correct for the effects of the stimulant. This pulls the system back to its original state, leading to things like caffeine addiction. In the ADHD brain, their homeostasis systems are tapped out, they can't get the brain to an optimal state. The stimulant provides an artificial push, that takes a load off of other corrective systems.

It's akin to glasses. Someone can learn to see through glasses, when they don't need them. However, someone who does need them will gain a permanent improvement from them.

Would ADHD even exist in a closed, perfect environment where a person’s intellectual and emotional needs are met?

Meaning some science fiction post-scarcity world where you can get everything you need by magic? ADHD would exist, but it is likely fair to say that it could easily go unnoticed. ADHD most stands out by its impact to interaction with other people. If you have no reason to interact with other people, then you can likely avoid the impact. It is possible for ADHD to even impact one's own personal interaction with themselves, but without interaction with other people, you're not apt to know what you are doing is any different.

But ending capitalism by transferring capital away from private interests to community interests is not that. All it would see is moving the capital to community interests. That capital still needs the exact same human involvement to maintain function. You are still going to go to work like you always did. You are still going to have to remember to pay your bills like you always have. There is no magic in that – just a slightly modified legal system.

Does ADHD exist in small, non-developed villages and communities?

A non-developed village won't know what ADHD is to diagnose it, but the qualities will be present in some people. I mean, ADHD is thought to be genetic, so if that community doesn't have the right gene line it might not exist, but I don't think that's what you mean.