Tu and Jag: I understand there are abuses. There are abuses by people who supposedly act on behalf of the "public good" too.
I am looking out my office window right now. I see a cruise ship, which employs hundreds of our citizens (a public good), provides a highly sought after leisure activity (a public good), and revenue to the community by way of the goods and services purchased by these tourists (a public good). I'm looking at a number of shops and restaurants who provide these same services to the public. These are, by and large, "corporations" (or some other business entity: partnership, LLC, etc.). They're all benefiting the public.
And yes "people" run these corporations: officers, directors, and employees. There is good and bad that comes with almost everything. I'm not denying the bad, I'm just saying is a definite benefit most companies provide to the public.