iPhone - cost or opportunity?

Well, actually there is a sort of race to develop something (really any sort of things and stuffs should be called "game") for this "new" platform. Lots of small developers, new aggregators and publisher are racing to put in the box something for this phone.
These market actors hopes that the rules of the game are supposed to be different for the iPhone games market.
Ok, distribution model is different with a no operator-centric model but at the end of the day the thing is the same: when the offer will be huge (and it is growing really fast) the client/gamer/iPhone owner chooses what he can easily recognize, so the things won't change, brands and ties in continue to win.
But there's another thing to consider. How many iPhones there are actually in the market? What's the sell forecast? What's the gamers share?
Nowdays I thinks that developing for iPhone is a cost rather than oppurtunity, port to this platform costs and takes time, and I'm not convinced that we will see huge sells.
What we will see for more than a year are just a few good ports of succesfull games, and lots of badly realized revamps of old games attempting to squeeze out the last penny from an unsucessful project or poor realized Tetris, Arkanoid and Zuma clones "iPhone version".

New life for the shoot'em ups?

Noticed?
After years of complete absence in the last months more than a big name in the mobile games industry developed and published some new titles of that old but fascinating genre named shoot'em up.
Ok I'm 37, so I played the original version of Galaga and Space Invaders and I admit I can't resist the call of a good shoot'em up.
The question is: why now, after years of silence, more than a publisher revamped such a genre?
Evolution? Involution? Perhaps who presses the button (industry, not joypads...) is just like me 37 and wants to correct this error?
Anyway, wathever is the reason... thank you for this second chance!