You are spot on with this. Could not agree with you more. However if they have a top flight NA already, and then a little something might help, and there are a few places left where there are still some top flight NA's being campaigned by some decent drivers.
MOst if not all front running cars at the Majors are $40K to $60k+, cars.
Most rotate out of their car every two or three years.
If someone thinks they are going to take their old (race car) NA and make a few changes to make it competitive, your wrong!
Sure. But, the rules apply to all levels of prep. So, while I agree they should be SET at the 100% prep level, every prep level is working to the same rule set. The theory being that cars of equal prep level (at any prep level) should be equally competetive.
My car is a 90% home built car, and didn't cost anywhere near that figure. And, it meets a surprising number of the items on dave's 100% build list---honestly, more than I would have thought. I do have a very nice drive train, and well-above-average(for a 1.6) chassis dyno HP/Tq curves. A Majors winning driver has said, "I could win a majors in that car."
As I continue to develop as a driver I will continue to develop the car as well. Someday, maybe I'l be a competitive on the majors level (maybe not). But, if I am good enough for majors competition, the car will follow right along (well, in reality...lead me there), with all the special grease, and whatever other wizbang things I'm missing today.