The problem I have with negotiation skill determining salary is that negotiation may be entirely unrelated to the actual job requirements, thus destroying true meritocracy.
In very few jobs are negotiating skills unrelated or useless to the companies needs. If you're the sort of person who can walk into your bosses office and convince him to give you a 20% pay increase, you're probably the sort of person who can convince a customer to agree to sign off on 50% more consulting hours. And that is a skill any company can use and should be willing to pay for, irregardless of what your job title happens to be.
There is a limit to how much the negotiation skill can get you - at least over the average for your position, that is. Mad negotiation skills can of course get you into mad paying jobs, but this is not the point.
When you fix the position then I think that the factors outlined in the article have a lot more influence over salary than negotiation skills.
