A lot of people are probably conflating the monetization angle with the content of the podcasts themselves. It's true that you're probably not going to see a lot of NPR or NPR-style highly produced podcasts from people just doing it for fun. On the other hand, quite a few actually prefer the more conversational and casual angle that comes from people just talking on mic or over the Internet. And those are very doable for pretty much anyone who has the interest and motivation.