Obviously we have hindsight now, but 2000-2010 was the absolute boom period of dedicated handhelds.
In the 1990s everyone but Nintendo failed to make an impact with a handheld. Even Nintendo essentially gave up on the GameBoy until years after it should have had a successor a game called Pokemon came out and kick started what would become this boom period.
We had two handhelds sell a combined 230 million units. That is insane and anyone who expected that to continue or grow had a very optimistic outlook. With phones such as iPhone allowing people to have cheap games on device they already owned we are now in a contraction or correction era depending on your view.
My best prediction.
The DS will forever stand as the single best selling dedicated handheld device. Why? Because that concept will likely no longer exist. Sony will very likely abandon the Vita leaving it as a niche product with Japanese third party support. Nintendo's next handheld will possibly go a few directions.
1. Combining their handheld and console into one machine
2. Making their handheld a phone hybrid
I think Nintendo can be viable because they still have the best stable of IPs in gaming and billions in reserve. That said, what ever follows the 3DS could be the last if their system is rejected by the market (sells less than 50 million WW).
