I always wondered myself. But the fact you can't correct a scratch at home is ridiculous. And
the BMW paint tech's evasiveness about repairing chips makes me believe that a Dr. Colorchip fix is out of the question, if you expect it look good. Then the the knock down sheet was crazy. All painter's should do a knockdown sheet before painting anything, new or respray. But when they showed the major differences in slight adjustments with hardeners, that means a repair is probably going to look like a repair and wont match the original paint.
So I guess if you see someone with a clean frozen paintjob, just assume they're ballers and have the car resprayed every year.