Ana Bray (Fan Art)

I think her family might have been responsible for the collapse. It's just a theory but with the resent lore with shadowkeep and the newest seasons it might be possible. Because on the moon expedition if you read the lore in the far in past they discovered a dark artifact which drove the research team mad and gave them 'nightmares' (sounds familiar) and at some point the Brays took over the entire operation and kept the team quiet. And now with the resent lore about The deep stone crypt (the origins of all Exos) which was also owned by them might have discovered a second pyramid ship beneath it. Because Cayde 6 had a memory of encountering a creature so dark it almost drained his light and Exos have dreams about the crypt describing 'a tower in an army of darkness' so think about it. Discovering that ship might have what lured the darkness to the traveller.