The only short-form pinball podcast I'm aware of is Pinball Profile (does interviews mostly focused on the competitive scene). But even that tends to be more in the 10-20 minute range.
I think the reason you don't see podcasts covering just pinball news is it isn't a good creative outlet. News reporting should be about objectively providing information. The enjoyment in putting together a podcast (in my view) stems from discussing opinion. That undermines the objectivity desired from a news show (since opinion is in play) and also undermines the ability to have a short format (it's hard to say much of substance when the time is aggressively limited). Given the written sources available (This Week in Pinball and Pinball Supernova being two that stand out to me), there is also the risk of just repeating what already exists.
Now, if you could have something like investigative journalism, that could be a new angle. But the way the game is played right now, since this hobby is so small, is your podcast either gets the inside scoop on everything and gets stuck under NDA (so you know everything and can say nothing) or you stay out of the industry contacts and get to speculate (but they also tend not to give you anything unique to work with). Coupled with how tight-knit the hobby is, it's hard to ask people who are doing a hobby for fun (which is the entire point) to do this.
Just some thoughts. My own opinion, long and short I like both formats. I have no issue being unable to finish an episode in one sitting, and to me five hours of content in a week is the same workload be it as five episodes or one. Podcast catching software is designed to make the experience pretty easy, and that's how I choose to consume.