Apple as a backer can be helpful in that regard.
And these are simplified physics. I have seen the amount of work that goes into developing physics. Ivory claimed that it took around 3 months to create a single car model from scratch, including physics, tuning options, modelling, damage, dirt, reflections etc. And not to forget the permission from the manufacturers for each part of alteration of these models.
I take the 3 months with a grain of salt. But it takes a lot of time and effort to make things right.
With the new consoles and higher definition and the ability to create more detailed physics, it will take even longer.
So it depends on the amount of people working on the game. And budget.
Assetto Corsa has a very small team. But also very experienced. They probably used a part of their revenues to buy new licenses. I bought their game in Alpha state. Strange way to create a game, but also smart, in case of a driving game.
In a sense pCars2 works like that as well, but you pay the full price, or more
The other end of the spectrum when it comes to car lists are the GT series and Forza. Both Sony and Microsoft take care of these licenses. They also have a seasoned juridical department.
Devs should spend their time on developing the game and not on licensing.
Fortunately Porsche does not do exclusive licensing anymore. They must have had massive critisizm because of the EA license. Exclusive licenses kill the gaming industry.
Maybe Eden games made a smart move teaming up with Apple. After all that company can buy a small country.
Maybe they will earn enough money to start TDU3 some day.