In this case of a small company, most of the marketing was done by lead director who was very close to the development team and obviously knew what the team was able and unable to deliver.
Also, I think the end result being as bad as it was in many’s eyes create feedback loop on the negativity. This is not the first time a game has disappointed its audience due to an overreaching marketing campaign, but this was not much of anything at the time of release.
You speak like someone that has never been a part of a software project.