OP: Why? Because they are on the systems who are having the fiercest war and they're the only two games of that exact kind for each platform.
Also, there's a lot of emotion and excitement attached to them, PS fans knows how important it (Gran Turismo) has been for their brand and x-box fans do as well and want Forza to become equally important.
They're likely to become the most influential, best selling and highest quality racer series on their respective platforms (and indeed already are) and are hyped and argued around accordingly.







