And there lies the problem. The USA is a large country. For some of the jobs being outsourced, 100k is an entry level salary. You have to compare apple to apple. For some jobs, 80k would be well above market rate. For others, 120k is pocket change.
When you add location into the mix, it becomes even more convoluted. You'd need a complex system that takes every role and every locations into account, using passed statistics, etc, else it would still be abused (eg: H1Bs working for a NYC firm from Mississippi or whatever. Or people "hired" for a "tech support job" doing software engineering).
The laws already have checks to prevent abuse. They're just not enforced properly. What is needed is someone to actually look and say "Well, if a foreign worker is replacing an -existing- employee, then obviously its abuse".
No amount of number tricks and magic will fix this.