The advantage of no camber change on a live axle is not a reason to really choose that setup. The choice of live axle is due to excessive wheep hop IRS get on 1/4 mile type launches which were designed to be the bread and butter of this type of car.
Saying an SS dominates in SCCA is like saying your kid is the best chemistry student, everything has a class in SCCA and many times there are problems with classification...move up to the higher unlimited classes and you are no longer talking about street cars.
The whole $60k+ car vs 20-30k car is a moronic one that the poor or middle class americans love to dish out. How their $7,000 400HP Vega can smoke a Furrary or Porch in the quarter, yippee ki yay! Thing is 1/4 mile times are probably the least important of the major bullet lists most people make while choosing cars. Creature comforts, ergonomics, and plushness are something the lower level cars MAJORLY give up. The interiors of even latest corvettes have been slammed and slammed again on the shoddiness and feeling as if you are sitting in a $10,000 basic car. You didn't save $40k to get the same performance of that 360 Modena, you saved $40k to get an engine and transmission capable of carrying you across the finish line at the same time. Might as well buy a 454 Chevelle SS and gut it, use a milk crate to sit on and tie yourself to the steering column.
Now the Corvette is a great performing car, it was designed to always be the 'world class' sports car the average american can afford. It's the blue collar dream and the SS is the baby brother to it. The corvette is not a bad car, but it's like comparing the girls in a strip club with $3 beers versus a club with a $50 minimum basically...both may have hot chicks, but one is going to have it at a much higher quality and also have less people coming before you.