I'm sorry, but you're kidding yourself if you think there's a lot of value in being an "idea man", or if you think that there aren't people who have both great ideas and the ability to see them through to completion.
Starter & Finisher are just different ways of saying that you need engineers who can build the foundations and get the project in a good prototype/working state. Yet, you will need engineers with a different skill set who are meticulous, product driven, detail oriented (however you want to phrase it) to carry it to the finish line.
I'd say both the original 80% team, and the remaining 20% team do about the same amount of work.
Now, just to "finish" my point, I'd say the 80% team definitely finishes their portion. They still have to get it in a state that is demoable and 100% functional.
However, I respectfully insist that I have made a successful career of being a Starter.