In your defense, I have never heard of there being an "opening night" without an actual performance, so I can see why you leapt to a mistaken conclusion.
Has there ever before been a Broadway "opening night" with no actual performance?
I think I mentioned this at the time it happened: I happened to have tickets to the rescheduled "opening night" of the most recent Glengarry Glen Ross revival. It should have been a tipoff for me that I wasn't asked to give up my ticket, but I was very excited and got a little dressed up. Then the performance itself was exactly the same as any other performance. No red carpet, no press, no speeches, no celebrities, nothing. I read later that what we would normally call the opening night party still took place on the original day. So the opening night really was just the release of the press embargo, and it sounds like that was what happened tonight as well.