I upvoted you. This indeed shows that PE systemically entered into 20+ territory only this century. Those are long-term effects, I'm not predicting a crash "this market cycle", but a systemic change in 20 years.
1. http://www.philosophicaleconomics.com/2017/04/diversificatio...
Progress!
The inflation adjusted one could be interpreted simply as continuing concentration of capital and centralization. What about the overall market PE of all publicly listed companies (whose number is steadily declining by the way https://finance.yahoo.com/news/jp-startup-public-companies-f... )? I cannot find that data at the moment.