In a recent interview, Kazunori Yamauchi from Polyphony Digital revealed that the development costs for Gran Turismo 5 have reached the 5.43 billion yen mark. This is quite respectable, but still not quite as high as titles like Grand Theft Auto IV, which had a 100 million US dollars. Yow.
In the same interview, Yamauchi also mentioned that the reason GT5 has taking so long is because they developed the game completely from the ground up for the PS3, bringing no old code or assets over whatsoever. The next instalment in the series, according to Yamauchi, won’t take nearly as long.