I see the causation in the other direction:

a simple tool is more likely to help you get organized and stay disciplined, due to the low activation energy to get started and keep using it.

Otherwise, there is a great temptation to futz around with your organization tools instead of making plans and getting things done.

I'm not highly organized or disciplined and simple tools still work better, but a single txt file is too simple. I've had good luck using Things 3 as an easy and flexible to-do list for tasks I will forget and I've been using Obsidian as a tool for everything else.

My takeaway is that the effectiveness of organizational tools scales with discipline and the simplicity of the tool removes organizational friction.

I don’t see any tool working if you’re not disciplined. Organization is just a facet of that.