That $100 billion has been spent many times over hypothetically by would-be do gooders, be it in the form of cheaper products, plants in the US, or whatever dreams people have for other people's money.
Look at the performance of our schools and tell us that we could quickly educate thousands of engineers, as well as doctors, chemists, and whatever else people want. Our universities are capable of doing that, but only if we allow a big influx of immigrants, which would have significant political obstacles. Otherwise, it would be far longer than a 3-5 year plan to build up a workforce.
I actually think it would be a good idea to bring in more skilled immigrants as it would help grow our economy. However, that's very difficult to explain to people when unemployment is high. Apple can't snap its fingers and get something passed. All of Silicon Valley as well as Microsoft and other companies have been jumping up and down for years that we need more skilled immigrants here, but particularly since 9/11 it's been a tough sell. Bringing in 100 engineers might allow a plant employing 1000 to stay here vs. being moved to China or India.