This anonymous Quora commenter offers remarkable insight into what could have led to The Talk Show moving from 5by5 to Mule Radio Syndicate. It’s a bit long, with a 10 point breakdown of what could have led to John Gruber’s silent departure. Here’s one I hadn’t considered:
Gruber posts a list of the talk show sponsors on Daring Fireball each week. This is worth almost as much as the daring fireball sponsorship which he currently sells for $7500 a week. I bet this played a major part in the negotiations.