It's a cool hypothesis of yours, that it's just a discipline issue. Unfortunately your typical lifestyle of a slacker you described was not my life, and I still struggled intensely, daily, with procrastination and getting things done and paying attention. I'm intelligent, had a good upbringing with strong study disciplines instilled in me, as well as a joy for learning and working. I want to be a fantastic worker and be highly productive, but despite all the advantages in life I have had, without meds my adult life is just barely staying afloat.
With ADHD meds, I'm suddenly performing like all my potential and desires suggests I should be.