This only provides evidence for Vlad Zamfir's hypothesis.

"Blockchain architecture is mechanism design for oligopolistic markets."

And it appears to be an oligopolistic market.

References

1. https://medium.com/@Vlad_Zamfir/the-history-of-casper-chapter-4-3855638b5f0e
2. https://medium.com/@Vlad_Zamfir/the-case-for-smaller-block-rewards-fb0eab38e15c#.md8ko1rdz
3. https://twitter.com/VladZamfir/status/843552270784614402