It doesn't matter what you know so much as who you know. Networking is the most precious currency. He met the right people, got the right guests, and surfed a wave of fortunate occurrences. He was roommates with Dylan Patel of TheIjnformation, and John Y of Asionometry, and has since developed a wide range of high level industry contacts.
Sometimes people succeed without earning it, and what matters is what they do with the success afterwards. I'd say Dwarkesh earned it, but got lucky and caught the right waves, and has surfed the hell out of his success. He's had consistently well informed, level headed takes, and has engaged the field with insight and honest curiousity.
When I see people surf like that, I applaud it. There's nothing grifty or shady, he's just had a great series of excellent opportunities and has played them for everything they're worth. Once he had a few billionaires on, that was all the social cache he needed to continue attracting guests and high level researchers and other figures in AI.