maybe I'm wrong but I think you're misunderstanding what I'm saying. I'm not confused about the laws that you mention, I'm confused about how those laws related to what I specifically said.
Although I'd seen the trailers in question before buying the game, when I bought the game the details of what what I was buying were stated on the PSN Store that I was buying it from, they are the details that would stand legally as a part of my purchase because they are what I agreed to when I was buying it.
If one of those trailers had specifically stated "you get this in the final game" and then I didn't get said thing in the final game and I was never informed that I wouldn't be getting it, then I believe that I would have genuine grounds to take action against them because they haven't fulfilled the agreement that we made.
This was all covered, to some extent, in relation to No Man's Sky when people took legal action in the UK against what was shown in the before that game was launched. There was a similar incident in the USA with GTA V when it didn't launch with the previously advertised online mode. I'm probably stretching the connection between the GTA V case and what is being suggested here though.
Unsurprisingly, neither of thee cases was successful and I'm not seeing anything that you're posted here which suggests that this would be treated any differently if somebody did attempt to take it on.
The thing that confuses me more than your suggestion that they are in breach of the law is that fact that you believe that they are but you, in part, "don't have time to deal with it". That is bewildering on a level that I just can't explain. If I felt that somebody had done wrong by me on a legal level, by god, it would be an absolute priority to deal with and deal with it to completion.
Again, I would suggest that if you genuinely feel that you've been lied to by the earlier trailers for Final Fantasy XV then, as you know, there are laws that protect you as a consumer and people really need to be standing up for their rights, even for stuff like this.
I don't think it makes me an expert (it doesn't) but I was a political officer for just over five years and almost every day of that was spent fighting for the rights of people who believed they didn't have the rights that were mandated to them by law. I just don't see anything being presented here that suggests that the law could be involved as you suggested it could.
We have different opinions on this, it's allowed, but I would be happy to see anything that could change my mind about how I feel about suggestion that this is a legal issue.