Cruz ending up with that 300 or so lead over Trump at the end is based on that. The author mentions in the article how Cruz has room to lose more than these predictions and still come out ahead of Trump into the convention.
More of the media every day is on board with the idea that we are heading to a contested convention one way or the other. Only the liberal media outlets are sometimes still pushing the idea that Trump is the inevitable nominee, because they are salivating at the idea of Hillary getting to run against such a weak opponent.
They attack Trump (not Cruz) because they fear him. Trump will beat Hillary like a rented mule.