"isn't there USUALLY an all-hands meeting around this time"
Years ago, it used to be that this was the time for kickoff and, usually, LE or one of the then co-presidents would show up. Usually. LE was notorious for never being on time or even not showing up despite being on the agenda. Traveling to kickoff got cut years ago and, with it, the appearance of and of the key execs -- with the exception of a pre-recorded message. The top level executives have been checked out of involvement with the "masses" for quite a while.
So a live appearance at an all-hands, even if it is a virtual/streaming event, is a significant change from the way things have been. I don't believe that LE will retire. He is too much of a narcissist to either let the company go in the middle of a battle (e.g. Cloud) or to trust his wealth that is tied up in Oracle stock to MH or SC. My thought is that it is an attempt by LE, MH and SC to avoid a mass exodus to competitors that are better positioned, are experiencing growth and treat/pay their staff better. It will be more Kool-Aid around how Oracle has THE Cloud for business and that the last year was just a taste of the success ahead.