Can you link to some evidence showing a slowdown in mobility? Also, I would assume a key metric to showing whether income inequality increase is a problem is to see whether the speed of improvement of standard of living is slowing or not. I'd like to see figures on this as well.
The fact that creating something people want is difficult is a universal truth, not an indictment of our democracy.
Not many mom and pops type business opportunities on the net.
Also, both google and facebook cornered markets that didn't exist 20 years ago. Where did that market come from? No one else got wealthy because of search or social networking?
That means risk. East German swimmer or Chinese gymnast kind of risk. For each billionaire there are such and such number of people who "got to grow as people".
In my humble opinion the swing towards egalitarianism was an anomaly in human history. Can we make this anomaly into a new status quo? Recent developments show that very unlikely.