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.

yeah there's always something a bit special in success, even if they took the idea, you can't just copy paste or you just produce shallow shiny stuff