Very interesting thread. I'm about to launch a site dedicated to promoting high-end audio, home theater and car audio equipment that is made in the USA.
http://www.americanmadeaudio.com (after 6/1) Defining exactly what is American-made for my purposes can be difficult.
Speaker drivers in high-end equipment are often made in Europe, then brought here into US-made casework and assembled here. Exceptions, like YG Acoustics or Zu, both of whom make their own drivers exist. Cables are often assembled here out of wire that was pulled overseas. Exceptions, like Cardas and those who use their wire, exist.
While there is quality audiophile gear made in every region of the world, the history of innovation and quality in the US is excellent and worth considering. Once you start looking, it becomes amazing to see what could be done. It would be incredibly easy to make a complete system only from components made in California, Colorado or the greater NY area.
The project started as a page on my music blog,
https://windhaming.com/american-made-audio-list/ but I started getting so much traffic on the page, and it's a topic I'm passionate about, so it deserved more.