Aww you poor thing, you have to actually do races to unlock cars instead of having them handed to you on a silver platter? This is blasphemy!
Last time I checked, ALMOST all racing games (other then those you mentioned) have you start from lower cars, and work your way up to higher ones. It's a fundamental part of racing games, and I don't see that disappearing entirely anytime soon.
You still have access to what you paid for in the GT series, you just have to work for it. I don't understand why gamers are so lazy these days. One of the fundamental aspects in ANY game, across all genres is progression (RPGs especially, other racers, hell, even FPS games), so why wouldn't that have a place in GT? 💡