Now, in their defense THAT is how most of these cars are looked at. They are not analyzed like you or I would do, they just aren't. They are really "good enough" if you want to be honest.
I do hear what you are saying and I too am amazed at how many people will look at a wavy car and say "boy now that is a straight car", are they looking at the same thing that I am. Many out there really dont have a clue what top notch paint work really is, or should I say dont really care. I myself when doing a full on paintjob will go the extra mile in blocking out till dead flat which is very time consuming and fatiging, but that is just the way I am. I recently have just finished a 67 vette that was an original 38,000 mile car so I started with a really nice piece. Still this thing took me about 700 hours to complete. Is it straight you better beleive it. Perfect fitting door gaps which is unheard of on these cars. A lot of work , yes it is but that is the difference when the car is finished and anyone who really knows what they are looking will see this. It really does come down to how far you want to go and how much time you would want to spend. I personally just cant stand buffing a car unless the body is flawless, after all that is the only thing paint really does is magnify the bodywork.