If Sony strategy is to this holiday season (including against the Wii), as a launching pad for major sustained sales through 2010 and into 2011, then yes they need to release GT5 in '09. If this holiday season isn't as strategically important to Sony as I think it is then GT5 can wait.
Alternatively: If it is ready to go then it should go. If they still need to iron things out then it would be a total disaster to release it while it was still a little bugish and lacking in polish. Then releasing game version updates via PSN.
“The fundamental cause of the trouble is that in the modern world the stupid are cocksure while the intelligent are full of doubt.” - Bertrand Russell
"When the power of love overcomes the love of power, the world will know peace."
Jimi Hendrix
