>what moral obligations do corporations have beyond following the law and trying to provide the optimal product to their consumers?
Corporations have no such morals. They are profit seeking social constructs. Breaking the law is often a profitable cost of doing business, as is making an ever increasingly shitty product when there is little to no competition.
Moral obligations, almost by definition, do not exist. That goes for anyone, not just corporations. They are the things you should do even though there is no reason to do them.
Arguing corporations have no morals is being pedantic. The question is clearly, what moral obligations _should_ they have?
Because it's in the common interest. The social contract doesn't "exist". It's an abstraction that people have agreed upon, in many forms, because it benefits the whole. What things we codify end up as government regulation. What things we don't are moral obligations.
Corporations have no such morals. They are profit seeking social constructs. Breaking the law is often a profitable cost of doing business, as is making an ever increasingly shitty product when there is little to no competition.