Again forum noise. If all the happy people would bother to discuss with the more active critical people your image would be much different. So much newcomers to the series expecting a sum of all its favourite games in GT5 and being disappointed.
For example this poll does not reflect the forum general ambient since day one:
https://www.gtplanet.net/forum/showthread.php?t=184706
Site Reviews is another history, most of them were from people used to arcade racers or console videogames and did not know what they are reviewing, not what you would expect for the specialized game that GT5 is becoming. Personally I'm not going to trust anyone that reviews GT5 with a pad, play in back view and gives more credit to a fancy menu than the options on it. At the end of the day is a personal opinion based on the reviewer tastes/knowledge. The game was punished mostly by the big delays and the hype, the reviews were reflecting that angry casual player view and tiresome.
Sim sites reviews were giving more justice to GT5. Also people tend to forget that the review copy of GT5 with 0 updates is not the same as the GT5 that we are playing now, not even mechanical damage existed. People like to judge GT5 as a finished product without knowing how good would be the final game once all the updates/goals ends. There are still much features being addressed. As KY said the game was developed like an OS structure to allow updated or new features in the system like apps and he did speak of one year more to full finish the game. There's no precedent in such game development aside of GT5.
About all the drama and concerns of the future of GT and KY not bothering what people really wants:
KY: Now it's released we're going to have several million people who'll become citizens of Gran Turismo. From here on we have to listen to their voice and see what they want and change the game accordingly to match their needs. So Gran Turismo really is just at the starting point, it's really the beginning and we're just going to evolve from here.
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That was in the same day that GT5 was out.