It absolutely depends on the child. I phrased it too generally. I like the idea of Montessori a lot, but it depends a lot on executive skills: being able to plan, start project, finish projects, etc. My kids both sucked at that, and I'm not great at it either. My oldest son, despite his stellar IQ, completely drowned in projects. No idea what to do, when to start, how to start, how to finish it, and even when he finished it, he forgot to turn it in. He simply needs more guidance.

He's now finally getting better at it, at 16, which is about time, because at the university, you have to be able to do all of this. I sucked at it in university, so maybe it's actually good that he ran into these problems earlier than that, but for him to actually finish school, it was not a good fit.