I've seen a lot of people talking about how Destiny will last for ten years, but that's really misleading. The documents released in 2012 as part of Activision's lawsuit against West and Zampella outlined a plan for four games, one every two years, with DLC expansions in between. This isn't a WoW-style ten years, it's a standard shooter franchise ten years. You'll be playing Destiny 4 in 2020, with this game being a distant, probably-still-confounding memory.
EDIT: Since apparently people aren't reading the part where I explained what the plan is, and instead are guessing at what this mysterious plan that was outlined in detail might entail, let me put it in Madden GIFs.