How fast a car will rust depends a lot on the country where it is used an also a lot on whether the owner has a garage where to keep it.
There are many countries where only a small percentage of the car owners also have garages, so the cars stay always outside, in rains and bad weather. Such cars rust completely far quicker than the cars kept in better conditions.
I had a car that I have used for 30 years and many hundred thousand miles, without having a garage. By its end of life, it still had many parts of the original motor, but from the original steel chassis there was nothing left. Every part of it had been replaced several times, due to excessive rust.
There is a lot more than that. Washing a car to get the salt off can make a big difference. Iron can be galvanized to prevent rust. Different alloys rust at different rates. Those are things I know about and I'm not even in the field.
There are many countries where only a small percentage of the car owners also have garages, so the cars stay always outside, in rains and bad weather. Such cars rust completely far quicker than the cars kept in better conditions.
I had a car that I have used for 30 years and many hundred thousand miles, without having a garage. By its end of life, it still had many parts of the original motor, but from the original steel chassis there was nothing left. Every part of it had been replaced several times, due to excessive rust.