This is a great start, but it needs some more patterns. "How/why <noun> <verb> <noun>" may well be the most popular Medium title construction, but I would suggest looking for a few more. Here's a few to start:
I was expecting a Markov chain manipulating a huge array of aggregated Medium titles but as simple as the cotton candy titles of Medium are so is this script.
"<verb> <noun> and why it matters"
"The day I <verb> <noun>"
"The <adjective> story of my <noun>"