On the other hand, the common sense approach says:
Can any of you actually imagine another Uncharted game on PS3? I've been playing Arkham City, and similarly I can't imagine another Batman game on current consoles. Another God of War? Or another Gears of War, for that matter? Most of the big series have been mined.
There's still plenty left to be done, but unless it's an annual franchise (like CoD or Assassin's Creed), I just don't see most studios (or gamers) able to stomach another entry on current consoles. Bioshock Infinite and GTAV will probably be the big send-offs. Like with Naughty Dog, if studios start making the transition now, it'll probably take them 3 years or so to make the leap to next gen specs (rather than the more typical ~2 years for well funded, ongoing franchises).
Assuming many dev studios started next gen development back in 2011, that still puts us into 2013-2014. Some studios looking to get the jump on next gen might cut some corners in order to cut down on development time--which at earliest puts us at mid-to-late 2013. But that's assuming they started last year. If they're starting this year, add another six months to those estimates. And if they start in the second half of this year, well, figure a definite 2014-2015 window.
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