You can learn more about this economist here

https://rogoff.scholars.harvard.edu/

If he's on LinkedIn you could reach out to him publicly and ask him if he did not know about bitcoin's use at retailers like NewEgg since 2014, and if he couldn't forsee how it would help people in autocratic counties, refegees, and everyone suffering from inflation.

Be sure to link to that news clip when you ask these things and mention that it was from 2018. You could also link to some sources to back up claims you are making that people will instantly try to dispute.

Newegg accepted it since 2014

https://thepaypers.com/payments/news/newegg-starts-accepting-bitcoin-payments-via-bitpay

Used by people living under a dictator

https://hrf.org/program/financial-freedom/bitcoin-development-fund/

Helping hundreds of thousands of refugees

https://www.da-ri.org/articles/bring-only-what-you-can-carry

A hedge against inflation

https://www.forbes.com/sites/digital-assets/article/how-does-crypto-help-hedge-against-inflation/

Remember, they are not arguing with you, they are arguing with the people who did the research, and the people who published it. So when you get responses falsely claiming your links are all propaganda, either ignore them or tell them they'll have to talk to Forbes if they think it's not a hedge against inflation. In short: don't feed the trolls, trying to reason with them will only fuel them more.

Also, keep in mind that the goal is not to humiliate Ken. It is to understand why his prediction was so far off so we can avoid these types of mistakes going forward. Don't be an ass about it. We all make mistakes and the important thing is that we acknowledge them and learn from them. Whether or not he acknowledges it and learns is not under our control, but either way, we can learn from his mistake if we better understand what he missed in his analysis and why.