^Again, the Typhon Pact isn't an "arc," it's just the new status quo. It's like the Klingons and Romulans being around in TOS, or the Romulans and Cardassians being around in TNG. There wasn't any endgame for those political relationships.
I'm sure you're right Christopher
, however when presented as a title, Star Trek Typhon Pact
implies IMO some sort of contained narrative (whether mini series, close ended series etc), otherwise why bother with a new title and not have the TP an ongoing presence in the currently-ongoing novel series?
It's mainly a sales/marketing decision. Destiny
sold well, so they wanted another big branded crossover event. That event,Typhon Pact
, sold well, so they wanted to do more of it. And it's because it is
open-ended that it's so easy to do more of it.
Also, while the Aliens in TOS, TNG and VOY were a part of the status quo (though something can be said in regards to the Klingon/Worf "arc" on TNG), DS9 did have a resolution-of-sorts to various plotlines regarding Cardassians, Bajorans and especially the Dominion.
Eventually, after seven years, and the former two continue to play a role in subsequent novels.