"Last independent automaker"? What about Avanti Motor Company? Lasted until 2006.
Much like Bricklin, Delorean or any of the various upstarts since then.... Avanti was considered a "Boutique" automobile manufacturer. I thought there was a legal requirement to actual production output to be considered a U.S. manufacturer but all I can find with a quick google search is that the vehicle must be assembled with more than 75% of it's total parts produced domestically.
Mr. Trump also changed the laws BACK so that if a small startup company wanted to produce automobiles, if they produce LESS THAN 500 examples in a Calendar year; they can gain an exemption to crash regulations and emissions laws which is what actually killed the Avanti Corporation.
But I'm sure we can all agree that AMC was the last true independent, large scale manufacturer. Bricklin and Delorean made about 3000 and 5000 cars respectively?
Avanti Corp. never produced 500 cars in a calendar year by the looks of things. 289 in 1983 was the highlight.
Avanti Production