Actually, they said GT4 would have it, to make it more realistic than GT3, but really, they just improved the graphics slightly
I know the length they go, they record every engine sound and do tests on them all so the handling and speed is just right, I didnt say GT4 was an easy game to make, that would be ridiculous, its just they could have done crashes if they wanted to, they just didnt bother as they knew it wouldnt gain them a lot of money, for the hassel they had to go thru, the game practically sold itself by the time it came out.
They say theyll do it in GT5 to keep you happy, whether they do or not thats a different story