Homebrew scene != Pirate scene
The homebrew guys are generally more motivated and talented then the pirates. Almost all console hacks come from the homebrew guys so that they can run their own stuff (and linux).
The pirates tend to take homebrew code and use it to run pirated games.
The entire time that PS2 had the "Other OS" option it was not cracked, because the homebrew community could already run their stuff. Compare that to XBOX and WII both of which have been broken a long time ago. As soon as Sony closed off the homebrew community, the inevitable would happen.
Of course its not so black and white, there is overlap between homebrew and pirates, but not as much as you might assume. Take a look at TeamTwizzers long campaign against pirates from using their code. They even tried in the beginning to have a dialogue with Nintendo about ways to support homebrew and keep the pirates out.
Going back to PS2; even with the "Other OS" option the advanced graphic features were locked, so homebrew games could never take full advantage of the hardware (neither could Other OS be used for pirate games). Some months ago a way was found for full hardware access, and not long after that Sony reacted by removing the Other OS feature.