I actually worry about a large-scale "privatization" of the stock market in the distant future. I believe that the concentration of wealth will get so bad that small groups of people will be able to create private equity firms capable taking all the largest companies private.

We are already to the point where there's so much private equity that startups don't need IPOs. So it's entirely possible that the next Google, Facebook, Amazon, Apple and Microsoft will never be exchanged on open markets.