That’s because, according to the rumours, the jailbreak method can only be done with a physical version of one particular game.
The game in question is Star Wars Racer Revenge, which, before the rumours, was selling for around $50. Now, listings on eBay are as high as $500, meaning that the price has increased tenfold.
At a certain point, if you want an open system, it's gotta be cheaper and less hassle to just get a PC than trying to start with a closed system and pay $500 to try and set up a brittle jailbreak of it.
EDIT: I guess maybe some of these people are trying to get control of their environment specifically to cheat specifically in competitive multiplayer games in a console environment, and I suppose that it wouldn't be the same on a PC for them, or maybe to pirate console-exclusive games that can't be emulated, but outside of those very specific niches...