I remember my parents getting the never needs waxing advice for their 1960 Rambler except the enamel was “baked on”.
There are arguments on both sides of this. I doubt there has been any scientific testing done.
Me, I go with the “wash it” side. But my own experience has been that if you keep your cars 10 years or less, the factory rustproofing is good enough, no washing needed. That’s over 5-6 cars living in the NH-MA area, lots of salt.
Simonize Glass paint protection really works. Just saying… one thing. Don’t use it if you are ever thinking of repainting.