Not to burst your bubble but that is how that hype mess got started.
As I understand and recall it: The showed a vertical slice as impression of the game, slapped a disclaimer on it to warn people its just that, a momentary tidbit and everything was still up for grabs. Them showing it was even under pressure from the audience.
By finally caving in, and making sure to let everyone know it was a demo of the then current state of the game with disclaimer and all, they were nailed to a pole.
So that accountability is worth jackshit.
I wish, really wish what you described was how it worked, but practise has shown otherwise.
Showing a vertical slice at conventions like the E3 is fairly common and I honestly doubt they were caving in, but more that this was planned. They wanted to build up hype since hype is what sells the game. This is not a bad thing, just the industry works to a certain degree. (There are outliers though, like Bethesda with Fallout 4.)
Also, I do not think that CDPR overpromised and underdelivered. Cyberpunk 2077 is roughly like the game they presented on both E3s and Gamescom. However, I also think that the people that expected a GTA in the future were the ones disappointed and unfortunately they would have had that connotation regardless, because a city set within an open world equals GTA for many people. As far as I can remember, even Rockstar had some negative backlash for L.A. Noire's lack of interactivity.
On the point of communication itself, I find the lak of communication a blessing. I just continue on with my day-to-day stuff, enjoy some CP77 between my other shenanigans and get 'pleasantly surprised' when another pacth would drop.
Its a carefree world that way for me
Would more frequent news prevent you from doing that? When I'm really interested in something, I soak up any kind of news just to get more. However, I do not have any problems in completely ignoring news I'm not interested in.
I think for fans Cloud Imperium Games' (Star Citizen) approach with frequent development updates and a more open communication is the better approach. While they also do not state any kind of release dates, they at least reveal more about what they are working on.
Also, you should remember that the game has been released, which is different from pre-release status where they were showing vertical slices. Now, many things about the game are set in stone.