It's going to kill his following among people who want to follow him for free, but by definition they don't bring him any money. If you have enough paying users, meaning your business gained momentum, you don't really care about free users anymore.
Some of the free users might pay. Small percentage “conversion” into paying users. But this can be done only once a large following was built and that model seems a bit disingenuous to me, free to paid, and I like the model where the content creator gives some extra to paying users.
Sam also does a number of live appearances, and I suspect that a number of free listeners would buy tickets once in a while to see him. It would be interesting to know if this move would decrease the popularity of live appearances as well.
Podcasts are spread by word of mouth. I will no longer be recommending it to anyone, and I imagine this is not unique to me. This kills the following it the long run.
Consider also the guest’s perspective. They want to teach a wide audience.
