You have to realize that the government has a vested interest in limiting the amount of visas under the thinking that every work visa they issue to a non-citizen means one less job available to a citizen. That's why it's so tough to get one: The company has to demonstrate that the candidate is so uniquely qualified for the position that they were unable to find a US citizen to fill the role.
It's why in any company that sponsors a visa they have to post the job opening and description in a common area, to give people the chance to challenge it and demonstrate that they can fill the position.
However, most companies have gotten really damn good and writing job descriptions to uniquely tailored to a person it's nigh-impossible for anyone else to possibly fit them, as I understand things.