You have to remember how this process was developed.. At the time of the Apollo program MIT was contracted to write the navigation software..if it was done the

You have to remember how this process was developed.. At the time of the Apollo program MIT was contracted to write the navigation software..if it was done their research way we would have never landed on the moon as they wanted an all approach. Instead what was negotiated between the engineers and astronauts was an approach where NASA radio signals carried the navigation stuff and the nav computers in the command module and lunar modules were backups and were not fully a full navigation of the full mission.