I think trying to say one is more important than the other is a false dichotomy. They are both very important. It's true that ideas tend to dramatically evolve

I think trying to say one is more important than the other is a false dichotomy. They are both very important. It's true that ideas tend to dramatically evolve as a result of execution. Likewise execution affords an opportunity for refinement that simply isn't there prior. I'd argue it's a different kind of refinement though from what you get while you're still in the green field stage. Thinking and research on their own—over the course of a very long period of time—offer insight that isn't easily gleaned under the high-stress environment of execution. A different kind of insight or refinement, if you will. It's worth noting that there are entire professions where the majority of what they do is think. Physics and philosophy come to mind. Why thinking is valued so little in tech by contrast, I don't know.