Yet another 👎 to dancardesigner.
I own well over 400 cars in GT4, and only about a quarter of them are racecars. Another quarter of them have less than 250hp. Yes, I have complained about what I call "dinkmobiles" in Gran Turismo, cars with less than 100hp. But, by golly, I own a few of them still, and do race them on occasion. If you want a challenge, try going from last place to first in a Suzuki with 60hp. Not even easy. Okay, it's not as thrilling as a Mercedes Benz E190, Ford GT or RUF, and certainly no racecar, but it's the freaking
challenge of it! Isn't that what gaming is all about?
And look, I love race modding cars in Forza too, it's one of the big draws to their series, being able to create cars. Well, until the arbitrary 360 car limit rears its ugly head and you have to dump something. So much for car collecting, which I hope isn't an issue with F3. But the thing is, it's the spectrum of motorsports that I crave. If Kazunori-dono puts a car into Gran Turismo, I'm going to honor him enough and the car to race it at least once. And I've only groaned over a very few vehicles, such as the Suzuki, trucks, and the Prius. Sorry, Prius owners, but I meh at your car.
And as said before, yes, Kazunori-dono has issues to deal with. Cars may not be available. Licensing can be a problem. Eventually SONY has to slap Kaz's hands and say, "Release the darn thing!"

Otherwise, I wouldn't doubt he'd rather release another upgrade to Prologue to squeeze in one more year's work on GT5.
If having a game loaded with cars of less than 300 hp makes you want to hurl, then Gran Turismo just isn't your game.