Yes, I am predicting that no console (except Playstation home consoles) will outsell the Playstation Portable anymore.
Wii U & PS Vita are failures compared to PSP. They won't achieve this, even 20M lifetime should be a hard number for each one.
Nintendo 3DS and Xbox One are not strong enough, they might get close but none of them are able to reach PSP lifetime numbers.
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-50M) 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. Smartphones are getting more important in our society and there is no way to change this anymore.
Next Xbox hardware: The next Xbox could be an adversary for the PSP, but I think the next generation will again be Playstation dominated so 80M seems not likely for the next Xbox.
New Playstation handheld: There will be no new Playstation handheld.
Google / Amazon / Samsung hardware: I don't expect them to have big chances in the video game market. They don't have the same experience like Sony, Microsoft and Nintendo.