If we want to be specific (and I believe that's always good!) I think the implicit question right now is whether the PSVita will be truncated early. You say this won't happen -- it didn't happen to the PS3, or PSP -- but there's lots of precedent heading in the other direction, too. The Gamecube died without ever finding its Monster Hunter to lift it out of the doldrums. The Dreamcast was killed extremely early and marked the end of the Sega hardware era. The Xbox 1 was killed early, too. So was the Saturn.
So I don't think it's obvious which way the Vita will go. In the recent past, Sony has propped up the PS3 to save it from tanking, slashing prices on a system which had already lost them a great deal of money; but would they be willing to do that again, in the financial state they're in? You can't keep doing that forever. On the other hand, the Vita may not even need that -- the PSP didn't.
This is the question, I feel. Will the Vita be another PSP (i.e. late Bloomer which ultimately does decently)? Will it be a PS3 (a platform which required significant financial investment to keep afloat)? Or will it be a Gamecube, or Xbox, or Dreamcast, which loses developer confidence so rapidly that the manufacturer decides to cut their losses and move on? Again, I personally feel it's more likely to end up like the PSP, as you do. But I do feel this is the implicit discussion just visible under the surface of many people's posts, and they try to avoid stating it outright, for different reasons -- Nintendo fans don't want to be seen trolling ("lol Gamecube"), while it's uncomfortable for any fans of a platform (not just Sony fans) to talk about their platform's possible early demise.
