Wrong. They've already stated that we ARE getting a Destiny 2 that is a true sequel, not just an expansion on the current game (what they will call it remains to be seen however). And when they stated the ten year thing, they meant that our characters and experience would continue through the whole ten years.....not that it would be the same game throughout the whole ten years. This is supported by them saying our character's cosmetics (the way our character looks, not gear or anything like that), class, and "achievements" will be carrying over to Destiny 2 while everything else about it will be a fresh start.
Seriously......anyone who thought that it would be the same game with just expansions added on to it for ten years are being pretty fucking stupid. Vanilla Destiny was made with 360 and PS3 in mind.....there's no way in hell they'd limit themselves that much for ten years straight with technology that was already archaic by the time Destiny launched.
Common sense people. Get some.