I don't think we need to define what public interest is in a perfect way, because different ideas undergo competition and selection process to be classified as public interest by the society at large. This is what happens today. When people care about global warming, reducing homelessness, etc., it's because these ideas became selected. What I'm wondering is if there's a structural way for these to be seriously considered when a company makes business decisions. Any system can be gamed, of course. But that doesn't mean we shouldn't have any system.

But the system already exists. Any company that thinks people care about global warming can start a global-warming related activities and people would support them. Any company that wants to reduce homelessness can start doing something about that, and if people think they are doing it right, they have ways to support this company, both by direct donations and by buying more of their products or services. Why any other system is necessary?