Thanks for the replies everyone. Based on the poll and comments, it looks like two things are happening:
1. Many people who have avoided US-based automakers for their entire life are willing to break that trend to own Model 3. This may apply to nearly half of Model 3 buyers (though generalizability from the poll is clearly questionable).
2. Many people who long ago abandoned US-based automakers are willing to break that trend to own Model 3.
I fell into category one, and it's pretty clear I am not alone.