I'm taking a bow. It's little known. I lived near York for years before I bought a neat book about NYC street names and learned the source.
It's a great trivia question. I had one Brit guess it was named after the Duke of York!
There's a public school on York and 78th which has the old "Avenue A" name in concrete.
Then again, Charlie is a complete idiot: "Wall Street can't determine the economy by those who buy and sell."