I see the appeal to private equity as a walled garden. Only elites get to invest in startups, and keeping the masses out keeps prices down (supply and demand). Depending on your outlook, you could say public markets are a bit of a ponzi scheme too. So dumping your private equity out onto the market with an exit lets you get in at the beginning of the scheme. Another big win.
The author says there are too many people in PE and the premiums are too high, but relative to public equity, I am really not sure. The author also mentions how bad the liquidity is, and that should also move prices down even further. So as far as economic opportunity it still seems like a good deal.
That being said, if I actually had $10 billion, I still don't think I would put more than 5% in because of how often startups fail and how bad the liquidity is.