what I find hilarious is that I haven't had a cell phone last more than 2 years in.... oh wait, FOREVER. In fact lately they've been dying before the 1 year mark is up (thankfully I've squeaked my last 2 in under the wire for replacement.)
There is no way I'm going to buy a cell phone that plays games, especially when normal cell phones already offer some, and future ones will surpass even that.
The you come to the question of Handheld. Nintendo will do it bigger and badder in the next gameboy (for less money too and backward compatibility.) and Sony has a handheld coming which will play PS1 games (or whatever.)
I'll pass on the latest get rich quick scheme.