Can't say it would affect my gaming experience that much either way in all honesty
..so exactly why are you this vehemently against the idea of rebalancing? You've just said that making these items more accessible wouldn't affect your experience with the game significantly, so what's actually the problem with other people wanting them to be more accessible - is that even a problem in the first place?
My question would be why should be make something more accessible that they clearly don't want to be particularly accessible?
Since you've been kind enough to provide some satisfactory answers to me, I shall do my best to return the favor.
In terms of making credits to buy these cars, it's this simple: the more achievable an item is perceived, the more likely I am to go for it. "Achievable", obviously, is a highly subjective matter. Some people consider it "achievable" if there's a vague mathematical chance of something coming true within their lifetime. Others don't consider something achievable if it takes more than an afternoon. The threshold varies from person to person, and that's all fine and dandy.
The issue I - and quite a few others, as should be evident by the amount of threads on this very subject popping up - have with the system in GT Sport, is that the 20-million cars aren't perceived as particularly accessible. And frankly, when you do the maths, you can see why: with the current grind meta (I know full well there are other ways of "playing the game", but because this is science, we're interested in making as many credits as possible), that's still 10+ hours of Blue Moon Bay'ing around per car. For some people, that's achievable. For others, it plain isn't.
At the end of the day, it all comes down to what you said before: enjoyment. Some people enjoy playing games in different ways. Why do you think Easy mode is a thing*?
Let's face the music: the only factor limiting access to the 20-million cars is just that - their price and the amount of time and effort it'd take to acheive them, potentially (*refers to number of threads so as to imply that "potentially" isn't really the right word*) limiting their enjoyment of the game. Why, then, should what at this point amounts to an inflated ego of some players - no names - come at the cost of the enjoyment of others?
I do believe that there is a balance to be found. A sweet spot at which both sides of the argument can agree that this is acceptable. Of the last three games, I say take a leaf out of GT6's (while the login bonus was still a thing) book: 5 hours of hardcore grinding at the most. It'll still take effort, but it'll be a lot more achievable to so many more players. Some might even say it gives them that much more freedom overall, and makes the game more enjoyable. And correct me if I'm wrong, but I believe more people enjoying the game is generally considered a good thing all around.
*Apart from in the Soulsborn games, obviously. Then again, if one has to refer to the Soulsborn games as a means to validate their point about a game being "balanced"..