Microsoft is right now hiring former Bungie developers/writers to steer 343 vision of Halo. Its clear that studio multiple atempts in trying to replicate Halo sucess failed every single time.
Every Halo from 343 dropped from the face of the earth in terms of popularity just some months after release. Destiny 2 is 3 years old now and its still played by some one million players daily. There is clearly a "secret formula" in play here.