I think it’s usually a good idea to allocate time and resources to areas where you have some competitive advantage. That is: do things where you have expertise, assets, connections, etc. and don’t do things where you don’t. For example:
If you’re an entrepreneur, don’t start a company that sells to publishers if you don’t know anything about the publishing industry and don’t have relationships with people in the industry that you can pick up the phone and talk to.
If you’re an investor, invest in companies where you have particular domain expertise and connections so that your investments can achieve higher returns than they could with another investor.
If you’re a big company considering a new product or business unit that has strong distribution channels to a given customer base, exploit that competitive advantage.