you have to remember that forsaken was trying to tell a different story to shadowkeep. forsaken was a revenge plot against uldren and the barons and ultimately led to the DC. shadowkeep was the set up for an even bigger story that will last to the end of this year (if not even longer) the point is, shadowkeep's story had to be ambiguous or cut off at where it did to elongate the story bungie wants to tell, whether it's through events in game in the form of dlc or through timegated seasons, this is how they're chosing to pursue it. forsaken's story was wrapped up by the end of the campaign, the dreaming city was the longer story that should hopefully end before years end.