Generally I'd lead into this with some flowery description, but let's cut to the chase.

We all see how every time we kill some bugger, they just come back at some point, yeah? Either a few minutes later in Patrol, or the next time we select that mission from the Director.

And we also know that we can come back from the dead by the grace of our Ghosts.

Clearly, our enemies have a similar capacity.

This entire war is a sham, a zero sum game, just a distraction while we see who can restructure to best be able to face the Darkness.

Because when it arrives, it will remove that boon from the Fallen, the Vex, the Cabal, and most likely it will do the same to the Hive, because it will no longer need them to harangue the Light. It can do that itself.