Wrong, BotW 2 was announced with "now in production" which is a later phase in the development process than "now in development".
And I stand by my point. If your game has a chance of coming out next year, you state as much in the trailer. It gets more hype, simple as that. You only don't put a release year on the trailer if there is no chance of it coming next year, because at that point a "2021" is just lame.
I guess I remembered it differently because I was watching the E3 Direct with German subtitles and translated back into English.
Your point is pretty bad if you delete the majority of my post when you quote me. "Gets more hype" doesn't work as a reasonable argument when it was only a good year ago that Nintendo teased SSB Ultimate as SSB in an April Direct. The game would have got a lot more hype if they had come out straight away with the announcement that it is SSB5, plus this was a game that released in the same year it was announced in.
Besides, for the negative nancies it wouldn't matter if the trailer had said 2020; they would have proclaimed 2021 as release year anyway. This is quite similar to how the release of Xenoblade Chronicles 2 in 2017 was doubted, because it's about a game that is too big and too demanding in development time to come so soon.