> "So-called patent trolls are not generally interested in shutting down infringers"
It's a little more complicated than that. First: they care mostly about the big-budget podcasters (like Adam Corolla, Marc Marron, Stuff You Should Know, etc.). If a bunch of little guys get shut down, they don't care because they weren't trying to extort money from those guys. Secondly, they have an incentive to keep their prices high to milk the big-guys. If they offer a "$10/year price to all podcasters", they can't effectively milk the big guys. They want the big guys to pay $10,000/year or more. This causes a conflict because you don't want to let the little guys pay a small price when you also want the big buys to pay a big sum. Perhaps they'll try to charge podcasters per-download or something (so they can milk everybody based on their assumed revenue), but that would be hard to track when we're talking about tens of thousands of podcasts.
Whatever the case, Personal Audio doesn't really have much of an incentive to keep a lot of small-time podcasters in business.
I mean, you could use traditional sales as an example. Businesses have an incentive to keep prices low because they want to sell to as many people as possible. At the same time, there's a limit to how low they want to sell. If you have the option of getting $10 profit from 10 people (=$100) or $1 profit from 50 people (=$50), you're better off selling for a $10 profit. It's not actually in your interest to sell to as many people as possible. Your goal is to maximize profit, and that means not selling to those 40 people, unless you can come up with some clever way to segment the market and still capture their sales (without pissing off your higher-paying $10 customers).