The PSP is the new Linux. Nobody really likes it, but it's a dream for hackers to fool around with
I'm kidding, but the home brew scene is pretty much the defining element of the PSP. I don't know if Sony even wants to make a valid effort to try and stop the leaks anymore because it's probably helping sales more than hindering it. That's a huge trend with gamers. You can make a good game, but if you make it modifiable, it'll live on forever. Quake III was immensely popular up until the last great wave of shooters hit with Half-Life 2 kicking it out of the spotlight. Trespasser, an old Jurassic Park game that served as a sequel to The Lost World, still has an active and fervent modding community that is bringing out new levels, models, and even improving the quality of the game through high-res texture packs and extra features.
Like I said, the home brew and modding community is unlikely to be hurting the sales of PSPs or the games. You can't convince someone not to pirate a game if they were already going to in the first place. A lot of people would just not play the game at all if they had to pay for it. So it doesn't make sense for Sony to continue to crack down on the hackers.
The PS3 may share the exact same fate. They're making a huge effort to keep hackers out, but if the system doesn't take off on its own, it might be a good idea to turn it over to the community to breathe new life into it. If nothing else, it will give the system a legacy to continue on.
Even if the PSP fails as a commercial device (unlikely), it will live on much longer than the DS because of what owners can do beyond the intended function. It would be lovely if the DS received the same sort of home brew attention--I saw a video of Doom running on it a while back--but I don't know if that'll ever happen.