Not entirely correct. Boeing, despite all the bad press, actually reversed course on this recently. 787's wing was made by a supplier, but 777X's wing is actually built in-house, right next to the main factory, starting from carbon fiber fabric.

How much can Boeing do this though? My understanding is in the past they used moving some of their production to a country as leverage to win contracts. They are a company that moved their headquarters to DC because management treats the product as secondary as if they make widgets. Until they reverse that they aren't moving in the right direction.