You're missing the point. People usually have that brilliant idea about an useful service while making a sandwich. If you don't act on it, it's worth nothing regardless.
> someone who doesn't have your cultural and intellectual resources
Unless you are a scholar at the very top of your field, there are thousands other people with the same background and resources as you, or better. A good chunk of them will have had the exact same ideas, plus a thousand variations. A handful will actually do something.
> choosing which idea to act on there are clearly better and worse ones
The act of choosing is the beginning of execution, and is way harder and more valuable than generating ideas.
> someone who doesn't have your cultural and intellectual resources
Unless you are a scholar at the very top of your field, there are thousands other people with the same background and resources as you, or better. A good chunk of them will have had the exact same ideas, plus a thousand variations. A handful will actually do something.
> choosing which idea to act on there are clearly better and worse ones
The act of choosing is the beginning of execution, and is way harder and more valuable than generating ideas.