I wanted to emphasized your comment. The ultimate goal of a startup is to create value (and its closest proxy i.e. money). The savvy entrepreneur will design a system in an "ecological " environnement that is part business, social, cultural... His startup is only a tiny part of that dynamical system. And he must take into account a incredible amount of fast moving details and/or have luck.
But of all those parts the most important one is the idea. Not because in itself it's a special idea but because, a good idea, is a summary of an incredible amount of experience. To use an analogy, formulae in maths and science are beautiful not just because of their elegance but also because of all the thought process that engendered them and all the implications they have.
IMHO an idea is the single most important value proposition of a startup and the part that need the most work.