A Question For Economists

Tyler Cowen is an economist.  I don't pretend to know much about economics except to say that most people who claim to follow Adam Smith haven't really read Adam Smith, especially his moral philosophy.  I also know that someone called economics the dismal science, but it's not really a science.

If I read this Cowen sentence correctly, he apparently doesn't believe that economics is dismal either.

If there were a new invention as important as the toilet, shareholders would not and could not appropriate most of the gains.

Given that fewer people are controlling wealth, I can't believe that shareholders "could not appropriate most of the gains."  I have an easier time believing that aliens will abduct me tonight than I do that shareholders would not try to appropriate any and all gains.

Because summarizing and responding to a book,  Cowen doesn't take the time to warrant this assertion.  I would like someone to provide a warrant for me.  Please leave a cogent explanation in the comments.