I think you are making a mistake in assuming that you know how another person, who presumably is much more qualified at this specific domain, should spend their

I think you are making a mistake in assuming that you know how another person, who presumably is much more qualified at this specific domain, should spend their time to be the most productive in that domain. That's kind of like telling Elon Musk that he should definitely use GTD - and if he doesn't he's doing something wrong - cause he'd be so much more productive. It is an interesting question why he doesn't want to collaborate with other people, but he is far from alone in that m.o. and he kind of answered it.