I'm going to say it is efficiency and the ability to implement ideas well, even if they are stolen ideas, that account for more of the success for anything else.
I also bet they did come up with some small things here and there themselves, in the process of implementing stolen ideas, because often things become apparent at the moment of implementation.
every day I wonder how come I do so few now that I'm paid compared to when I was jobless and hacking prototypes for $0
finding the recipe for creating goal driven, high speed, high quality, frictionless teams is a difficult quest