I think it’s also important to consider TFS was the end for a lot of people. It didn’t help that Echoes and Revenant weren’t super well received, with Heresy being the best but a bit too late.
IMO content vaulting was what killed Destiny, as that’s what it’s publicly known for.
To the people confused why Destiny died:
The Edge of Fate expansion was very lackluster gameplay wise and introduced weapon/armor tiers alongside Portal.
This effectively killed 95% of activities and loot in the game because only Portal & Kepler dropped them. Cont.