It's a really good article that explains why the author doesn't support trickle-down economy and support "middle-out" economy, which relies on strong middle class.
An example I found enlightening is the diminish effect of wealth on purchasing power. "If you are 1000 times richer than the average American, and an average American buys 1 pant a year, you are not gonna buy 1000 pants."
I am sold to this idea.