There is, but it's really low, and most Americans in the field that meet those credentials won't go for a salary that low because other companies will pay more. There's also the issue of credential inflation to meet the req.
There is, but it's all can be circumvented. I had an h1b and was doing the job of a programmer (65k prevailing wage). I officially became "junior database administrator" with 43k prevailing wage. As the time progressed, I started doing the recently departed IT manager's job (120k), yet my petition was for "computer system analyst" with 60k. And I got kicked out after 5 years and 6 months (meaning I had 7 months left on my visa and thus no chances of getting a new job). It's a very stinky business.
I am an Indian and I loathe these companies. Not only do they exploit visa program in the US, because of these companies the IT job market for an entry-level engineer is fucked up in India. The salaries are very low and the work culture is terrible. They literally hire thousands undergrads in their final year and train them to do mole monkey work for next to nothing.