Experience is non-linear though. X years of parking your butt in a chair staring at code doesn't make you an expert automatically, it doesn't even necessarily make you better than someone who has only spent 2 weeks learning the language or platform. I'd rather have a JWZ, Brendan Eich, or Linus Torvalds in their 20s working on my project even if they didn't know the language than some paycheck coding drone from the enterprise trenches who has a million years of experience in doing mutate-compile-repeat development in the exact same development stack.
That's because most corporations seem to define experience incorrectly. Experience is not simply time. Instead, I prefer Hunt's definition of experience: "By experience, I mean specifically that performing this skill results in a change of thinking. As a counterexample, consider the case of the developer who claims ten years of experience, but in reality it was one year of experience repeated nine times. That doesn’t count as experience."
Unfortunately, the reality is that most companies equate experience with years; just look at the typical job postings as an example of this mentality.
