"Doomed" how? As in being dropped after a year or two? As in being a total money sink for years like the PS3 was? Really the Vita is looking to be reasonably profitable (not being sold a huge loss and Sony makes back money on memory cards and games). And I really doubt that the Vita is going to be dropped like the Dreamcast was when Sony is a major corporation. They've heavily invested in the product. At the same time, it's not like the Vita was the first system to have a shaky start. The PS3 was in a FAR more dire situation than the Vita was (especially since Sony was losing billions on it), and now it's the best selling home console almost every week.
Not that I think it's going to smash the market or soundly defeat the 3DS or anything, but it's far from being "doomed." I think it will end up being a reasonable success. I mean, geez. At least when people were saying the 3DS was doomed it had actually had a worldwide release. Let the Vita release in more than one country first.
