Many employers (mostly big ones) tailor positions so Americans can't qualify. Tricks like changing the job description to include something the Americans dont have after the interviews are common.
Saw one company do this. They hired 5 H1b's. Only one guy could actually do any of the coding. The other 4 just pretended to work while he did everything. But they were cheap.
The way they actually work is to first select the guy they want to hire, tailor the job description to his resume, paying particular attention to obscure skills, and so have the description be something only he can fill
There's also the trick of allowing the favored job seeker to lie about his skills, making him seem to be at a higher level than he is, and lowball the salary offered so that people who really are at that level won't be interested
Also, about that 80K applicants: the visa is renewable for up to 6 years, so if the limit stays, we're talking about 80K * 6 = 480K foreign engineers