Why are all these big name people willing to go on his podcast?
At best an interviewer's credentials are a poor proxy for how thoughtful their questions might be. Since you can hear the questions themselves why bother with the proxy?
Stephen Wolfram's episode has not many rather is pretty much almost all like that. Dr. Wolfram and Lex clearly seem to be on very very different planes throughout.
I found this again to be the case about with John Carmack's session.
Questions that I would have placed would have been what would be a 3D engine look like if Carmack is commissioned to build it today that must be cross platform? What technologies he thinks have future and if then in what direction.
Only explanation could be that maybe that's not the purpose of the podcast at all. The goal is to just have aimless, low caliber, ordinary conversation to keep it approachable for a wider audience.
In addition, he created his podcast in 2018, and a youtube channel in 2006.
"Fridman began his podcast in 2018. It was originally titled The Artificial Intelligence Podcast"
It just goes to show that with a little credentials, a little intelligence and consistent effort, after 17 years, goes a long way.
Tell me a case where someone who has all 3, after 17 years didn't have something to show for it.