It would be really fun to have a car that is completely corrosion-resistant, but it's also solid, safe and does not require much worry. And do not think that it is not interested in car industry at all.
The legendary "Delorean DMC-12" from 1981 to 1983 had a waterproof body made of stainless steel. He gave her another characteristic feature, just as the design of the upright doors and the design of Giorgetto Giugiaroa is inadequate.
Stainless steel is widely used. It is likely that a kitchen sink, knife, stove and other items are produced. Stainless steel is not completely corrosion-resistant, but under normal circumstances, things made from it can undoubtedly stay for hundreds or even thousands of years. Why not use it in the automotive industry?
Indeed, the answer is not complex. We mentioned the Delorean DMC-12, which is really interesting, but looking closely, you will see that its surface is very rough.
The incomparable, brilliant DMC-12 is extremely difficult to maintain, and the surface structure is very uneven. Many customers just painted their cars to get a great shine.
Moreover, the body of the Delorean DMC-12 is not made of stainless steel. Well, such metal plates are made of this metal, but behind them lies the structure of glass fibers. The stainless steel cone is so slender that the structural functions are not entrusted.
Such a double body was difficult enough, but it would be even more difficult if it was made only of stainless steel – this metal is very dense and firm.
Regarding hardness, did you notice that Delorean DMC-12, your knives, stoves and other stainless steel items have similarities? They all have straight lines and even surfaces.
This is due to the fact that stainless steel is relatively difficult to form. Of course, it's possible – your sinks are a good example. However, the formation of conventional steel is a much simpler and cheaper process. Stainless steel is even hard to warm.
Finally, the stainless steel itself is quite expensive. People do not want to drive the same car forever.
They want to change the car every few years, and car manufacturers want to sell as many cars as possible. The stainless steel body would be very expensive, and people would still be free of these cars in time.
And alternatives are better. Carbon fiber reinforced plastics is a material for future bodies. It is durable, but it can easily shape complex shapes.
If the automation of components from carbon fiber is resolved, the production process will fall.
On the other hand, conventional steel can be protected from rust, and now it is successful, so it's simply not necessary to switch to a set, heavy, non-corrosive and heavy to carry stainless steel.