>> business isn't just about "execution" of an idea into a product
The ability to execute is not limited to engineering. It's also applicable to the business side (ability to successfully secure funding, find product market fit, create a marketing and pricing strategy that works, etc).
The other thing is that you cannot neatly separate ideas and execution. As you break a high level problem into its components, there are ideas at every lower level that will allow you to succeed. A high level idea cannot succeed without the supporting lower level ideas (strategies and tactics) in a variety of disciplines (marketing, product, engineering, etc). If we take Facebook as an example: many people at several universities had the broad idea, but only one set of people also had the lower level strategies and tactics to turn that idea into a multi-billion dollar company.
My take on this: good high level ideas are worthless without the appropriate low level supporting ideas.