You really believe that? It's a wage depressing policy profitable whether the labor is "unavailable" or not.
The Indians I work beside in IT earn pretty much the same as locals for equivalent skills. The construction workers make scale.
At my other home they are buying houses and driving up the price of houses and still able to buy them. I don't know what all of them make. But I do know what many of them make and it's pretty decent.
It should be noted that in both IT and construction and many careers, the wages vary greatly depending on one's negotiating skils. When I started at Motorola HR claimed that entry level MIS with a BA all started at the same rate. That was a lie. It varied from $14,000 to 58,000 for exactly the same job description. Since then I've worked beside programmers who made $16,000 and $300,000 and the guy making $16,000 was more competent and worth more money to the company; but lacked self-esteem and negotiating skills. He loved his job so much he would do it for free. The overpaid guy knew little about IT but was a great bullshitter and negotiator. I made $75,000 at that time and was between them.
Last Sunday in church a lady got up and gave a testimony that she got a 20% pay raise because she had been faithful in giving money to God. It turned out that many of us who don't tithe also got nice pay raises. (Mine was 15% starting May 1 which puts me even higher in the six digits.) Law of supply and demand. There is a demand for workers and not enough people willing to work.