Yes, I am predicting that no console (except Playstation home consoles) will outsell the Playstation Portable anymore.
Wii U & PS Vita failed, we should be happy if they could reach 20M lifetime.
Nintendo 3DS and Xbox One are not strong enough, they will be close but none of them are able to reach 80M lifetime.
Next Nintendo hardware: I think Nintendo won't bring us a surprise hit like the Wii anymore, the next Nintendo console will sell typical Nintendo numbers (20M-30M) and won't be a danger for the PSP. This also applies to the next Nintendo handheld, the handheld market is shrinking outside of Japan because of the smartphones and we can't change this anymore.
Next Xbox hardware: The next Xbox could be a big adversary for the PSP, but I think the next generation will again be dominated by Sony so there is no chance for the next Xbox.
New Playstation handheld: Well, we know this will not happen after the Playstation Vita...
Google console / Samsung hardware: I think they have no chance in the video game market. They don't have the same experience like Sony, Microsoft and Nintendo, they don't know how this market works.
Wait, so what you're really saying is that they won't ever outsell Gameboy Advance anymore, since PSP could't even do that. I see.