I've always heard the brain was the most complex thing that we know about. And I've always heard that brain surgeons spend a considerable amount of time planning some operations due to the complexity involved (although I am sure not all operations).

The brain being incredibly complex is probably right, but my guess is that our ability to slice and dice it in beneficial ways is probably much more limited.

Still though, yes, in some activities you must do your utmost to get it right the first time.

It's also not an either-or choice. Sometimes you can plan to do two weeks of work, then observe, then do it again.

I think it's a mistake to view the spectrum as only having two spots, total planning and completely inductive. Learning how to mix and match is probably a better skill than blindly following either extreme, imo.