Would it be possible that the first two trailers were made in the previous years when the game was still work in progress and the current graphics are much better, they just haven't shown it to us on purpose yet?
I don't get the complaints about the graphics. Overall GTS graphics were already good enough. A PS5 GT pretty much needs to improve drawing distance, lighting, detailing on track surroundings, FPS and grid size. Dynamic time and weather is also important. Out of all this, only the lighting and detailing around tracks can actually be seen in a single comparison photo, while every other improvement that the new console may allow, can't.
At some point people will realize that games have reached photo realism, and that the reason to buy a new console (or improve their PC) is not the graphics. In the future we will reach a point where both photo realism and FPS can't improve any further, so the focus will shift to more NPCs/AI in the player's vicinity (or bigger grids in racing games), more players in online lobbies, instead of drawing distance, maps will be fully loaded the entire time, etc.
GT7 has way more things to worry about than graphics.