AND 

The Ferrari 458 in ocean's sig.

Wrong. There's already the technology to simplify the process of adding cars. If a GT game comes out 10 years from now, dozens of cars could be added each day. They are scan rooms. You drive a car into a 'clean room' with a 3 dimensional scanner than scans the entire outer surface of the vehicle and creates a dangerously accurate 3D model based on the object. The technology already exists, but is mainly used on smaller and less complex objects. In even 3 years time, the technology will be there to do it on an object as large as a car. The only thing the creators would have to input is maxiumum depth so it doesn't try to draw out what it sees 12 inches inside of your radiator support or 24 inches into your engine bay from below the car. They'd also have to input a maximum number of polygons so it doesn't try to create a movie-like 3d model with 1 million polys. You'd have trouble getting any console to render a race full of those, even 5 years from now.

As for the size problem, it will follow Moore's Law. The amount of storable memory increases exponentially in a given amount of time. A 500gb 2.5" HDD is cheap and easy to come by right now. The external drive on my PS3 is a dual-bay enclosure stuffed with 2 x 2TB 3.5" hard-drives... the whole setup cost me less than 300 bucks 6 months ago. Combined with my internal (320GB 2.5" HDD I paid $85 for), I have a total of 4416 GB of disk space on my PS3. And it all cost me less than $400 shipped to my door. In 2 years time, It would be possible for me to have roughly double that amount of disk space for the same price. In 10 years from now (according to Moore's law), I should be able to get ~140,800 GB of disk space for roughly the same price (after adjustments for inflation). Given these figures, its very possible home consoles 10 years down the road will come to your door with ~10 TB (10,000 GB) hard-drives, with larger models coming out later into the generation. Games will be largely distributed via download at that time, and internet speeds will likely cripple what we have today, so downloading a 25GB blu-ray should easily be done within an hours time.

Gaming is reaching a plateau, nothing more. Plateaus can be surpassed. Technology is being created every day to simplify the things we do. When you're making a video game based on actual real-life objects you can easily obtain when needed, integrating them will be easier than ever. 

Oh, I don't doubt that the technology to allow faster processes in which to model cars. I was only using the reference from PD in current GT premium car modelling. It took them almost 6 months to fully render accurately a Premium car. So if anyone took to the endeavor of rendering 10K cars, with the current standards, it would take them a lot, lot of time. Not even PC sims which have a vast modding community working constantly have been able to pull those number of cars, as far as I'm aware.

I don't doubt that HDD sizes 10 years from now will be in the TB range, that's exactly what I said in my response to MARCUSDJACKSON  

We can also have amazing internet speeds by that time, but if we also have an optical medium which can also store a large amount of data (like 200 or more GB), wouldn't it be also a viable choice, on par with digital distribution as well?

Mazda RX or Nissan Z or maybe Mitsubishi Eclipse, as for the color of the car I prefer silver. There's so much to choose from which I like! ^^