I have been telling this to my colleague a couple of times and finally there's a nice chart to back it up - smartphone game revenues are now killing Nintendo and Sony's portable gaming sales. Of course the chart doesn't separate between iOS and Android but lump it together, but this shows that Smartphone gaming is definitely more profitable and it makes a lot of sense.
As you can see from the pie chart above, the market share for Smartphone gaming kept growing while Nintendo and Sony's kept shrinking. While Sony was smart enough to launch the Xperia Play to gain some market share on the Smartphone gaming side, its own Sony PSP is rapidly losing market share.
If you're actually wondering what's the reason this is happening - its simple. Everyone wants or already owns a smartphone. And since smartphones today have some serious firepower to play console-quality games, its only natural that many would buy them off the Android Market or App Store. Compare that to a dedicated portable gaming device - it may not really appeal to all because its just that - a gaming device.
But a smartphone is a portable gaming device, a phone and erm...a mini computer I suppose where you can surf the net, listen to music and the works. So you have a powerhouse device that can do lots of things. Obviously this is the trend now and we will most likely see the Portable gaming market diminish very very soon.