I think it's simpler than this. I don't think there is much outright gaming of the signal. Programming interviews and programming competitions are very simila

I think it's simpler than this. I don't think there is much outright gaming of the signal. Programming interviews and programming competitions are very similar, much more similar than programming interviews and real world software engineering. When you are selecting top programming competition competitors, you are implicitly selecting people who will absolutely smash your (non-design) programming interview questions. This has little to do with their effectiveness as software engineers.