Don't we all. That's why Polyphony will need to be more aggressive in their post-launch support through game updates (such as adding in more cars and tracks, especially at a larger volume than in GT Sport). It could take time to build cars and tracks for the game, and we don't know to what extent Polyphony may be outsourcing.
In GT Sport's credits, I read there are at least 17 names in the "car modeling" section, and 56 names in the "car modeling artist" section, don't know if this makes any difference or if this is ever the same.
If like, say, Polyphony has 50 employees in the car modeling team, and it takes six months to build one car for the PS5 alone (one person is in charge of one car), it would mean that they could potentially finish up to 100 cars in a year at most, but well, Covid and restrictions per country slowed everything down. Just imagine if they all outsourced someone, or a group to work on the models, in which the finished models would take three months instead of six, that could mean 200 cars in a year.
I sure hope Polyphony would give us certain real-life licensed liveries as part of the default color selection in Arcade Mode and Brand Central (just like in the Project CARS series) if this was the purpose behind renaming most of the race cars, and that more real-life liveries get added via DLC through game updates. This is not just only for JGTC/Super GT but for almost every real-world race car featured in GT7. Good thing in GT Sport, headlight colors and custom wheels are part of livery creation, so I hope the extra liveries in the color selection would change things like the wheels fitted, tire branding and headlight colors, besides sticker placement.
Here's the thing, Forza has a different post-launch support strategy (featuring a "car pass" that covers seven months of paid DLC consisting of seven cars each), expansions, mostly paid stuff. Another is, in the case back then, with Motorsports 3, 4, 5 and 6, their DLC support only lasted less than a year (eleven months at best). GT7 is likely going to be long-term like GT Sport, so who knows how many cars we'll end up getting (we could get a huge number of cars at the end of GT7's lifespan).