What should the value of a private sector company tell us?
A company's value, in financial terms is given by its equity, or its difference between its assets and liabilities. The well known expression $E=A-L$ reflects this. When you buy a share, you buy a part of the equity. The point is that since the world we live in is dynamic, decisions today affect outcomes tomorrow. As a result, when you buy part of this equity, you are buying part of the claims on the firms' expected future profits. The market rewards those goods that consumers demand more with a higher price and one can definitely make the argument that a firm's future profits are conditional on it producing goods/services that are valued by the public. Whether or not the goods themselves improve the lives of consumers is a separate question altogether. Do we always buy goods that improve our lives? What does that even mean?