I think people who have more energy (ala endurance athletes) look more disciplined.

Also what kind of energy you need to be a President, Chess Grandmaster or a Tennis Grand Slam winner is different. They all are called displined though.

People with disabilities and mental health issues who do well are usually those with high energy levels or are in environments that produce energy more than drain energy(distractions/triggers etc play a role here).

You can also see it in areas of poverty. People who do well are usually called more driven, ambitious etc which basically again goes back to energy levels.

Stephen King definitely has more energy than GRRM. But Martin has proved you can be as distracted as you want and still suceed if you have an imagination and are social.