The backbone of any game is risk versus reward.
Cannot disagree more. The entire point of a game is fun. I'd assume GT is fun to people who like cars and enjoy driving. I see nearly everything else as really annoying fluff.
The best games I own are pure sims with no progression what so ever. They have (relatively) large and devoted fan bases, and these fans typically occupy themselves with bettering their skill, or being creative (as most of these sims allow for sandbox style play).
If you want to relates things to risk/reward, where is that in GT anyway? It's impossible to not make money in GT. You could finish last in every race and still have the same garage as a perfect racer. Also, because you need to unlock stuff, focusing on just having fun is discourage. 24 hr race, you need to do it to unlock car X. How many people are going to go into the race with an "fair" car if they're racing just to get car X? How many would race it "fairly" if they were doing it for fun?
And where is the lack of reward for winning a competitive 24 hr race with a fair car
that you actually wanted to do in the first place.
If everything was available from the start, there would be no risks involved and no reward for winning, so why bother?
The risk is not being fast enough to win the race, the reward is winning the race.
95% of users would play the game for an hour or so and then trade it in for something else.
I doubt this to the highest extreme. What happens when people beat all the (limited) A-Spec races anyway? The game just flies to the nearest garbage dump? There is an entire section of the forum dedicated to players using the closest thing to sandbox GT has, online. League racing.
Effectively it would stop it being a game and turn it into a tech demo.
Right now it's just a chore list.