I don't know about that. Just to even get an idea of what you want to edit, you need at least the amount of time it takes for you to review your raw material, which in this case could be over 2 hours sometimes...
(I work with a lot of audio, though no podcasts, so I may still be underestimating a bit)
I think you and your GP are right on. I edited a short-lived podcast and regularly spent 1.5 hours producing and editing each 25 minute show. Even if you're using good equipment and have a solid connection, producing a tight podcast necessarily takes more effort than is obvious to the listener. That's kind of the point.
Final reasons might be another point why podcasts without much preparation and only the necessary minimum of post-production are common. I don't know the economics of podcast networks but a post-production infrastructure similar to traditional media would probably be go beyond the financial scope.
I think we are mainly talking about the kind of editing where you delete an entire section because it never got interesting.
Unfortunately, these are live podcasts for the most part so there is no real incentive to do that... you already put it out once as a finished product so why spend more effort on it?
(I work with a lot of audio, though no podcasts, so I may still be underestimating a bit)