I suspect Apple will replicate what they are already doing in Brazil, where Foxconn locally built a factory to manufacture specific Apple products to the local market.
Note two things: 1. I suspect this would be a Foxconn factory, not Apple (note how Tim Cook says "we'll be working with people"); 2. The total investment of the Foxconn factory in Brazil was 5 times bigger, so I suspect that Apple's $100m would cover only a fraction of the total investment required to build a factory in the US.
Regardless, that's good news for the American worker.
They don't need to replicate what they're doing in Brazil if it's still more economical to manufacture in China. The difference with Brazil is a whopping 60% import tax on pretty much anything, which would make an iPad cost about 1,000 USD minimum if they didn't make them locally.
Note two things: 1. I suspect this would be a Foxconn factory, not Apple (note how Tim Cook says "we'll be working with people"); 2. The total investment of the Foxconn factory in Brazil was 5 times bigger, so I suspect that Apple's $100m would cover only a fraction of the total investment required to build a factory in the US.
Regardless, that's good news for the American worker.