Exactly, there's no way you can produce 2+ 2 hour podcasts a week without them being a rambling mess - or you have dedicated script writers and editors and the one reading them is just the voice of other people's text.

Any podcast should be prepared and scripted to some extent, especially shorter ones. Especially good political comment/talk shows. Unprepared 15-minutes interview podcasts are just as annoying to me as very long one.

This relies on the moderator / podcaster to have sufficient time / manpower to prepare, or sufficient authority to convince guests not to come without any serious preparations.

On the opposite, there's a podcast from the German Newspaper Die Zeit that has made the long rambling its concept. It's called "Alles gesagt?" and consists in a usually unedited interview with two journalists. The interview (in English or German) stops when the guest considers he has nothing more to say or pronounces a magic word. Yuval Noah Harari's interview lasted 10 hours IIRC. It's decently prepared, but that's not the kind of podcast you can listen to regularly.