If you are defining hype by the amount of money spent and the way the critics reviewed the game then your concept of hype is wrong.
Hype is creating an expectation of an experience and failing to live up to it. In that regard, I would say Destiny's "over-hyped" is actually very minimal. They did an Alpha and a Beta. They literally gave people every opportunity they wanted to see how the game played before the game was released. The majority of their marketing did not touch on the story or promise an amazing cinematic experience. We as a collective group just assumed it would have that. The marketing, like for so many other games nowadays, was vague and barely touched on anything beyond "this is a shooter, made by bungie, here is what a few websites had to say, go buy it please". It followed the same formula as many other games ads do at this point.
I think a few large reasons why people call Destiny the most over-hyped game ever are simple. First, it is the most recent game that grew a groundswell of anticipation and was met with good, but not great, reviews (yes, reviews in the 70s are actually good scores. Games do not need to be 90s to be good people). Second, despite the game not advertising a great cinematic experience, people assumed they might get one from Bungie because of the story they did get in Halo. Last one I will bring up, is the MMO elements of the game. This is the one area that I think Bungie dropped the ball in. They didn't want to call it an MMO because of the stigma of MMOs, but didn't want to not call it an MMO because that is essentially what it is.