"Suddenly" is a polite fiction, to make things more palatable.

Things started to decay with Nixon. By the time of W. America was probably doomed. Obama's unwillingness to enforce the law on the right and powerful was likely the last straw.

After thirty-two years in America, I personally made the most expensive decision of my life, and fled to the Netherlands in December 2016, so I certainly put my money where my mouth was.

A little further down, the article actually does explain that this had been inevitable for years.