I mean, even though I don't think it's likely, they announced more DLC in the September direct, and not E3 that year.
As for Steve, I legit don't know how 2020's reveal schedule would have worked were it not for covid.
January: Byleth(Okay, this makes sense.)
March: IT'S ARMS....but we need more time, the arms are tricky to code(Okay, sure).
June: Min Min revealed, got it, THEORETICALLY, Steve should have dropped at E3, but then you have an issue.
Let's say that Steve was revealed in June, with a release date slated for Fall... where the ** does that leave Sephiroth? Because in no way do I see ***ing Sephiroth dropped in the September Direct.... and yet, we have never gone a Direct without a new Smash reveal, so what the * would have happened in September?
Steve almost has to have been the September Direct reveal for any logic to make sense, but if Steve was an E3 reveal, then September has NO reveal.