It's true that the corporation making a profit benefits the shareholders, but that doesn't mean the purpose of the corporation is to maximize this shareholder benefit. The corporation obviously wants to attract and retain shareholders, and so it must give them sufficient return on their investment, but that's it. And giving the shareholders value isn't at all the "purpose" of the corporation, it's merely something it must do. You may as well say "the purpose of a startup is to maximize return for VCs"; that's certainly what the VCs want but that's not a healthy mindset to be conducting business with.