well, there are small start ups and engineering firms, back when things were considered "open" and the taxes were fairly low...a lot were doing under the radar

well, there are small start ups and engineering firms, back when things were considered "open" and the taxes were fairly low...a lot were doing under the radar type stuff and using the HK-Shenzhen connection to get rapid prototyping done and so forth. I know of a few companies doing LCD panels for stadiums, a few fabless chip design firms going for embedded markets, etc. But no "unicorns" in the American sense.