I see this a lot (I'm looking for work). What makes me wonder about these employers is why they don't promote someone in-house (most positions I see advertised have a Supervisor or "II" after the title).
There's too many positions requiring many and very specific skills for all but a very few to qualify for. Employers are asking just a little too much, especially for what they're willing to pay.
One more thing: how is it that Americans "don't have the required skills" but foreigners do?
A refreshingly funny ad I saw was for a customer service representative that assisted customers over the phone. The job requires 6 months customer service phone experience, but paid for a 6 week training program (yes, 6 weeks!).
I find that employers promote the most inept employee. Its the ones that work hard and make less are left on the bottom wrung. And in this economy, you’d be crazy to voluntarily leave a job.