This was before they used clear coat on paint. Your paint would dull, but it could be buffed out with a can of wax and a really good arm work out
If your car starts to look bad from the outside, using a car polish can fix the problem. Most often, simply washing and waxing are not enough for making your car look brand new and fresh. This is the reason why there is a need to polish your car; you can make it look like it just came off the assembly line ..