They say GT Sophy can only drive 340 cars though. I'm on PS4 so I cannot check, maybe there is someone who has compiled a list of what cars GT Sophy cannot drive. It's certainly more than just the Tomahawk and Chaparral.
I've almost driven every car in the game (only about 120 left). Some of the VGTs are just plain BAD to drive because of low ground clearance, too much power, too little grip and wonky unfinished physics because of their concept nature. Try the Porsche, Jaguar and Italdesign VGTs around the Nordschleife and you'll know what I mean.
GT not for me when I have bought and driven every car in GT1, GT2, GT5P, GT PSP, GT5, GT6, GT Sport and GT7
But having been there done that, doesn't mean I like the grinding system and there are clear examples from other games that does it better.
Driveclub - you have around 200 unique events in career mode, thanks to dynamic weather and time and carefully curated Championships focusing on particular car classes. You still need to progress and earn XP to unlock cars, but by the time you finished career mode you have enough to unlock everything. None of the races feel alike so you don't get bored, and you get to sample every car in the game without repeating/grinding one particular race 100s of times.
Project CARS - all cars and tracks unlocked from the start in free play mode so you can just jump in and drive whatever you choose upon buying the game. But if you want to slog it out in slower cars first you can also do so in career mode. Unlike GT where if you buy the special edition you can destroy everyone in Sunday Cup with your Castrol Supra, despite the game forcing you to buy a Mazda2 first
Assetto Corsa - I can buy the game and within minutes set up a custom race with a full grid of 917Ks all with unique liveries. You try to do that in GT7 - you have to grind 20 million 20 times, then search liveries and apply them one by one in GT Auto. God knows how long that will take.
GRID - you start off in slow cars and work your way up. You need to buy cars but the credits rewards increase proportionately in the endgame races. By the time you finished career, you have enough money to buy all the cars and free to do whatever you want.
Objectively, there are ways of making progression fun and reasonable without forcing someone to repeat the SAME race for 10 hours just to buy ONE car.
Subjectively, some people like to be a masochist and follow the cult of Kaz. If that's you, go ahead but me and many others don't share the same view.
For machine learning to happen live on home consoles you're looking at several generations ahead. Who knows if Kaz or GT is still around then. The computational requirements are just multiple orders of magnitude beyond current home consoles.
Also you're creating a situation where every game copy has its own unique AI. Your copy of GT10 is going to be different from everyone else. How does that work from a user parity point of view? If you're a slow and bad driver your Sophy is going to be dumber than everyone else too. Or they will learn to drive dirtier and dirtier. The gameplay is going to be 180 degress completely different for each copy. Not sure PD would like people uploading videos of Sophy driving like Wreckfest.
I can see in the future where everything is cloud based and you just stream the AI code from PD's central server. That way every race every person does updates the central AI, and everyone benefits from the updated code simultaneously. But you only have to look at how popular game streaming is right now, and the myriad of connection problems that still plagues always online titles to see this is still very very far away.
By that point, you might as well just race online against real people.