If PD would add more than 500 cars or more then I prefer a $49 season pass. Or Driveclub-like updates (x paid cars, x free cars, delivered each month).
As for tracks...I believe they should be free. But yeah I am disappointed by no de la sarthe, spa, silverstone, laguna seca at launch. I hope these tracks will be available on the future.
(500 cars divided by 4 classes - N, 3, 2, 1 = 125 cars each class, expect ~31 unique cars homologated. Gr. X does not count, all those are concept cars
)
If you want all those 500 or more cars for free then PD must find a way to get total sales beyond GTA V.