You're the type to ignore process and only look at results? (or you genuinely don't know how GTS was at release?) GTS eventually reached higher numbers at 2019 (the report of it being sold 8 million units), and at that time there were already several offline and old content updates, it now has significantly more road/production cars and an offline mode such as GT League (don't think it's anything good, just probably it can be a draw for some to buy). GTS after many updates are quite different to GTS at release (which was what I refer), and a good number of updates are old content seen in more typical GT to draw in the playerbase that longed for older GT experience (particularly offline go-ers).
Why is it irrelevant? I mean really GT7 was made as something not only racing even in the official description of the game itself - "Whether you’re a competitive racer, collector, fine-tuning builder, livery designer, photographer or arcade fan – ignite your personal passion for cars with features inspired by the past, present and future of Gran Turismo™" and I was pointing that out. It wasn't only talking/listing about competitive racer only.
You only know present GTS and not GTS at release? I know the different opinons that people had formed on the game between GTS at release and present GTS (which seems to be the only one you refer to), and the process on how it can improve people's opinion about the game.
That's actually my point of using another solution to deal with those. All of those are what I want too (and I talked about GT6 being minimized as a game as complaint, it has events half GT4's numbers, also less than GT3). I always wanted for GT events to make use of as much cars as possible (and at least also varying levels like GT3 had - prefer GT2 format of listing though, so events like FR Challenge aren't merely some starter events).
At least for cars being matched with a field of appropriate cars, GTS Arcade iirc now gives rewards (Cr, etc.) after complelting a race. The AI problem though applies to any aspect of the game, not only player career. That's already obvious they should be improved that I won't need to bring that up.
What I want as well in GT. They've only touched upon this a bit in GT4's Arcade cars and GT6's Recommended Cars, but never really committed in it. Would make car division easier as well instead of listing every cars such as NASCAR race in GT6, if not for events determined by car year (like Historic Racing Car Cup) or country (like Schwarzwald Liga), and can open up aformentioned events easier like Kei (where otherwise I'd thought of Kei event in Japanese Events like GT4 or such) or SUV (where GT2 had the likes of Station Wagon Cup but obviously, as it's only given hp limit then you can use any type of cars).