If Activision was making this game, it'd have been out 3 years ago with 10% of the cars, 30 tracks total (including alt. configurations), horrible graphics, and it would've still cost $60.
I'm annoyed over the delay, but I really don't have a right to complain considering how much better Polyphony does racing games than any other company.
I just think Kazanori is a little too skeptical of the patch system. I'm sure the game could easily be released in any state right now (after the spit and polish of menus, of course) and any 'perfecting' he wants to do could be done in patches within the next few months after release.
And thinking about it, something tells me we aren't going to have much in the line of for-profit DLC. Consider - at the rate their going, they've more than established that they're going for a quality game rather than a "good game for profit." If they're going to add anything later on through patches or DLC, it's either going to be free (and include 1 or 2 tracks and new cars to be added to the dealerships) or it's going to cost maybe $5-10 and be absolutely ridiculous. Either that, or they'll just sit on everything until GT6. Lord knows we have enough patience as Gran Turismo fans. They could get away with it.