It's as if you've forgotten that FF VII Remake was originally announced during a Sony conference. I'm sure a lot of money was involved to get it going, at this point it's prolly contractual to show it off for Sony. Your own example goes against what you previously said, with a KH3 trailer here and the demo on SE's side. I'd say showing a demo is borderline required at this point, most games and companies don't announce something at E3 then go radio silent for three years. With the reported development hell, showing a solid demo would put a lot of people at ease.