This is pure speculation but my hunch is that the Scott Alexander of a few years ago wouldn’t care about being doxxed. I agree with your take on this. Become a well known writer on the internet and doom yourself to being forced to live by the principles you articulate. It gets claustrophobic and cognitively dissonant after a few years. I think he didn’t want to be married to the content he’d created forever, was looking for an excuse to shut down the blog, and when this NYT thing happened it was a blessing in disguise because it allowed him to shut it down without losing face.
I think Scott Alexander would be very sympathetic to this line of reasoning too.