I would argue that it’s not that the trailers are getting better, it’s that they increasingly are put together by people who are completely disconnected from the movie. It’s long been the case that trailers aren’t done by the directors of the movie, but by studios. This is why trailers sometimes reveal critical plot spoilers, or contain seemingly big moments…that actually got cut from the movie because they didn’t really fit the story. None of that is new.
But it does seem like the ‘art’ of putting trailers together is becoming more and more formulaic. They know how to randomly select moments, use music and tempo and then string them together with other moments to imply something completely different than the movie actually is trying to do.
There’s a million recent stories where directors see the trailers only after their public release and their reaction is basically “WTF is that? That’s not what the story of the movie is about at all!?!”