I think a big part of being "horrendous at being self-directed on long-running, large-scale, multi-step tasks" comes from not being trained on that set of skill

I think a big part of being "horrendous at being self-directed on long-running, large-scale, multi-step tasks" comes from not being trained on that set of skills. I'm not so sure it's an inherent human trait. The traditional school system, at least in the US, is almost entirely focused on training obedience and completion of relatively short-term tasks. Homework, tests, maybe the odd paper that's "due in 3 weeks" but really can be done in a mad dash the night before. Until someone tries to go for a PhD, they may never have needed to plan and execute a large-scale, long-running, poorly-defined task on their own before. School didn't train for that. And they're expected to undo 20+ years of that step-by-step spoon-fed approach, throw that all out the window... and learn a new way of working, mostly on their own, and tackle this huge project. No wonder the failure rate is so high.