Saw the rear end removed off a new Discovery Sport yesterday for the fitting of a tow bar. Not a trace of any sort of wax or such like covering on any of the metal behind the bumper. Even worse how ever was the inclusion of two pieces of dense foam behind the bumper and under the light holes which presumably where there to stop noise transferring. Each one was removed and wrung out producing easily a pint of water each !!

Yes, thats a piece of water soaked foam sitting on top of a lightly painted panel. Thinking a head, with the amount of salt we throw on our roads over winter, that will be a pint of salty water in 6 months time.....

That's sadly the reality with these products these days, there are solely aimed at the first owner, with no thought for longevity, once they are out of warranty, manufacturer couldn't give 2 fncks.

i tend to disagree. all cars thesdays. are electro-static primed. meaning they go though a dip tank, and a charge pulls the paint on. then they go through other tanks, before final colour is robot sprayed. the undercoats are enough to last the lifetime. meaning you really dont need rustproofing, unless high stonechip areas, like cill and wheelarch, (away from plastic liners)
nowadays, when we see old cars going to the crusher, we rarely see rust, in fact they often look too good to be crushed! im sure the bumper on the disco Sport has an airgap between the foam, and the rear valance. What we think we see, is not what we could actually be made aware of. and water against the plastic cover, is not really going to kill it.
its true that cars of the 60-70's were throw together, on non-strike days, and the paint often put on (seemingly) at the end. a good underseal, was a wise investment.
however, any minor paint fault, done by the automated treatment, means that all cars will be the same.
unlike 'Friday afternoon Bob's' paintjobs, of the seventies.
its not just the cars' electrics, and reliability, that have advanced over the years.

Hmm... my Classics and even my (admittedly under 4yo) P38 had far fewer reliability problems than my 322s. The Classics were bad for corrosion, but my 2012 car has been poor also. Only Range Rovers since 1988