Shawn Layden confirmed in PS Blogcast today. Biggest reason is that they didn't want to build anticipation for not much news.
Not sure if already posted.
"Now that we have Spiderman out the door, we're looking down in 2019 to games like Dreams and Days Gone but we wouldn't have enough to bring people altogether in some location in North America to have that event. We don't want to set expectations really high and then not deliver on it."