Its been 3 and a half years and NOW there understanding the Cell?!

[Twistedpixel]

Actually its about 4.5->5 years for the Sony first party developers because development started before this generation began.

Edit: hmm 2010 vs early 2004 (May) for sampling which means being conservative they've had early chips on boards and developing with them since late 2004 which means at release Naughty Dog would have probably spent a little over 5 years on the Cell CPU.

http://www.tomshardware.com/forum/128078-28-sony-samples-cell-processor

So yeah, its taken half a decade of work to get 70% of the potential out of the CPU. The remaining 30% is in using it more efficiently.