I'm not reading 12 pages of this topic. I don't even own a PSP.
If development, production, and marketing costs are exceeded by gross sales revenues, then technically its a success for Sony.
This is business ... Capitalism!! ... so really that's the bottom line ... did it profit? The N64, for example, was considered a 'fail' by many a Sony fanboy 15 years ago because the Sony Playstation outsold it. But the reality was, on console and 1st party game sales Nintendo made astounding profits on N64. So it was a fail from the teenage gamer perspective, but a huge success for the corporation.
Whether the PSP made Sony a profit or not, though, I'm sure to the average legit consumer the PSP has been a massive fail. Which is why I think the amount of hype the VIta is getting among young hack/mod/flashcart gamers is exaggerated. You might be looking forward to the next awesome emulation powerhouse (once it gets hacked), but most PSP owners are probably thinking 'nope ... not making that mistake again.'