I agree with your scenario, but I wouldn't consider someone who consistently under-delivers a "rock star."

This is why defining terms is important. For me, a rockstar is a developer who is just further along, who likes to program in their own time, who reads Hacker News, and builds projects on the weekends. Within 5 years, that person will be much further ahead than the rest and will spot pitfalls, security, and performance issues simply because they have encountered them before. However, sharing that information could lead to that person being called a "rockstar" and problematic, hampering "progress".