Quote that perfectly sums it up. (Destiny)

by Cody Miller , Music of the Spheres - Never Forgot, Thursday, September 15, 2016, 21:44 (2789 days ago) @ squidnh3

"When we made Halo games Microsoft owned the IP, but we acted like we did. When we finally owned our own IP (Destiny) we let Activision tell us what to do, like they owned it."

The difference is here that at the end of the day, Bungie has the nuclear option. They can, pending the completion of game/expansion subcontracts, simply stop making Destiny games for Activision. Right now this isn't as much of a threat, since Bungie is only 3 years into a 10 year exclusivity publishing contract, and would have to try to create a new IP to work on if they were to split from Activision. However, this option becomes much more powerful once they start getting towards 7ish years in, when contract renewal negotiations begin to develop. If Destiny is still going strong at that point, it's unlikely that Activision would want to lose it to a competitor, and Bungie would have a very strong position at the negotiating table.

They would have to scale their games back considerably. Remember, they went with activision in the first place because there were really only a five publishers even capable of giving them the resources they needed for Destiny, and only two that they'd feel good about working with. Ditching Activision would de facto mean going to MS, and MS knows this.