Microsoft has always done tons of big elaborate setups for press announcements for more than just video games, and that's only gotten stronger since apple envy struck the business world. Really everyone in the tech industry has been getting into fancy keynotes since Apple made it so popular. I assure you there is no trend away from keynotes. If anything, everything is moving the opposite direction.
Nintendo is the only one scaling back, and it really makes no sense why. People say it's because people will learn about the products some other way, but that's not the point of advertising. Everyone knows coke and budwieser exists too, yet they still advertise constantly. It's not just about making people know about your product, it's about getting people excited about it.
If they needed to scale back, sure go ahead, but to full on cancel it is really troubling.