Except this leaves out any organization that pays below market rate for exceptional talent. That might sound like a good thing in the face of it, but consider such organizations include: national labs, early stage startups, software foundations, etc.
Also, unless you cap it in a per industry basis (which makes the whole thing very inflexible to changes in the economy) you just created an insurmountable problem for those firms that want to hire, say, a Catalan interpreter. Required skill uncommon in the U.S.? Check. Easy to get a foreign worker with that skill? Check. But now you need to pay them a software engineer salary or higher.
As a matter of fact, given how small the cap is, you could conceive that the only software engineering jobs that would be hiring internationally would be in high frequency trading and other such areas of the industry that pay higher salaries. Or, software engineering, but just in the bay area (other places pay less because of adjusting for the cost of living). No matter the rest of the considerations associated with why someone chooses a particular job.
