Yeah, the current iteration of Destiny is nearly three years worth of content with four different Raids (that you can play currently in meaningful ways with up to current LL rewards) with a ton of Strikes and multiplayer maps outside of the main story campaigns from vanilla to Rise of Iron and all the Patrol stuff (three original planets, one moon, and two additional playspaces from the expansions). Also, consider modes like Prison/Challenge of the Elders and SRL Racing.
Which leads me to the idea that a lot of players are going to have to reign in their expectations a bit just for the fact that Destiny 2 is going to seem a lot thinner content wise than what we have been used to over the last few months with the AoT update. Hopefully, there are improvements concerning content and replayability with the addition of Lost Sectors, Adventures, Difficulty Modifiers, etc but the fact still remains that we will have one meaningful Raid, one story campaign, eight or so (give or take) Strikes, and whatever the initial game ships with regarding multiplayer maps/modes. A meatier story campaign all-around and more ways to explore and more stuff to do in the Patrol areas will help a bit but Bungie is already up against it considering what the current player-base is used to (four Raids, etc).