I don't think any system is doomed. No system has failed to at least be moderately successful in the market since Saturn, correct? Or am I forgetting one? Even DreamCast lasted for a few years and a lot of people played on it.
PS Vita doesn't need a giant install base to be successful. How do you measure success? PS Vita owners, according to Sony, spend a large amount of money on download games and accessories, more so than other systems. So you can't just go buy physical packaged sales and say "Oh, that system is dead." As long as there's a large enough niche, any system can survive.

The Screamapillar is easily identified by its constant screaming—it even screams in its sleep. The Screamapillar is the favorite food of everything, is sexually attracted to fire, and needs constant reassurance or it will die.








