We have nearly 1000 good cars missing. Most of which would be seen as a bigger priority over the ambulance. Of the nearly 500 cars, there are duplicates, VGTs, Gr.4 that are just slightly modified versions of the existing road car, and so on. Not every car, or every type of car, is everyone's cup of tea, which means, if a new player comes to the game, expecting it, being a 2022 game, to have a decent selection of modern cars, he/she will be disappointed. You don't solve this, by adding random stuff.
It's not really subjective. It's objective. The moment you don't have any criteria, you end up with a random assortment of things, and a lot of fans pissed off because less and less of their "favourites" are being added. And this has become the reality of this game. Fans of specific brands or specific types of cars expected to be in this kind of game, get completely shafted. This gets worse when you are limited to 60 cars per year, which PD doesn't even bother to achieve in GT7.
Meanwhile, historical significance is not subjective. Just because something is significant for you (lets say, your 20th birthday), doesn't mean it's significant to everybody else.
Specialness, is also not subjective. The Mazda 3 we got is not special, meanwhile the Mazda 3 MPS is.
Fun is subjective, sure. But is not limited to driving a specific car. There are cars that are more widely regarded as fun cars to drive than others, which means that, for the greater audience, they would be better additions to the game.
Sure. People can find fun in virtually anything. Doesn't change the fact that, spending resources for a giggle and a laugh, isn't a smart way to do it. Having a pool in your home is fun, but if you don't have resources to complete building your house, you shouldn't spend them on a pool. GT7 doesn't have a great car list, being quite terrible for some brands and/or segments, so why not try to fix that first.
I used to play in cruise lobbies (and "cops and robbers" type of lobbies). It's still a niche playstyle, that can also be played using any other road car in the game. One of the best ways to enjoy such lobby, is having a great sounding car, and do flybys (overtaking) with it. Everytime you rev the engine, it's special. With that said, a good sounding car, is often a car that is somewhat fast, which means it has use on a racing game that goes beyond cruise lobbies.
Swaps aren't really an argument. PD could model any other car and give it a swap. A Ford RS200 with a Ford GT engine would be something amazing. But a Ford RS200 is not a priority, nor fun to drive, nor historicaly relevant, nor special or unique.
You should do the statistic for all the pace cars vs their normal counterpart.
The suggestions forum was used a lot. But PD clearly never bothered paying attention to it. The McLaren P1 has been somewhere in the top 10 for 10 years, and is yet to make an appearence. Nowadays the suggestions forum is outdated, and doesn't include cars that were in GT6 but didn't make the cut for GTS/GT7.
The suggestions forum could also be improved. Instead of a thread per car, make it a thread per brand, and then inside that thread, people would ask, and vote (with reactions), for the cars from that brand that they want.