There is no nuance. The society where anyone can become the best worker will produce better workers, and more of them. Cast systems aren't for quality signaling

There is no nuance. The society where anyone can become the best worker will produce better workers, and more of them. Cast systems aren't for quality signaling, they're for limiting what any given person can achieve. It would be foolish to factor them in to anything, unless your aim is precisely to surpress others.