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.