The problem is that it is actually a "shortage of (cheap) tech workers". Quality is expensive, and companies don't want to pay for expensive american tech workers when they can cut costs by paying for cheap overseas tech workers.
Writing a web app can be done by anyone in the world. Writing a driver and understanding intricacies of an operating system, fewer. Creating and implementing new algorithms? Well...
Sucks to be them. US somehow killed its huge research advantage enjoyed by years of successful brain drain from all over the world.