They same did that... FM5 and FM6 has cars with models from 360.So if they gone gt route, the game would release with 20 tracks and just shy of 100 cars. Big yikes.
The difference was these 360 models are way better than PS1 or PS2 models used by GT5/GT6.
But now what happened with GT on PS3 is happening here with FM8 because the difference between the models is becoming evident.