Really enjoyed this article. But I think you've given to much credit to decision/will fatigue. It's not something we just run out of after x amount of decisions. Its going to be unique for each individual, weigh heavily on the rewards available for self-control, levels of stress, and numerous other factors.

Also, setting a goal means you have to choose to stick to it. Even if its strict you're still deciding to change your schedule as well as, actually do whatever it is your goal is over some other option. There's always a trade off when changing habits.

You could probably write separate articles on each of these three pieces with a lot more depth. That'd be an exciting set of reads.