http://blog.5by5.tv/2012/5/18/coming-soon-big-week-with-dan-...
Probably coincidental, but TTH was a tent pole show, and Big Week appears to be one as well.
I also think that bringing in Dalrymple might have made 5by5 feel too crowded. To my knowledge, of the 5 or so major podcasts on 5by5, Talk Show was the only one hosted by a blogger. (Though I'm hesitant to call John a blogger because he rarely writes original content. 95% of DF is links or quotes with one sentence of analysis, but that's neither here nor there) Dalrymple was only the second blogger, and Gruber must have felt that Jim was stealing his thunder.
Frankly, I think it's for the best. The Talk Show has been going down hill, and can't hold a candle to B&A or Hypercritical.